Western Gas Partners LP (Form: 8-K, Received: 08/09/2018 10:05:22)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): August 9, 2018

WESTERN GAS PARTNERS, LP

(Exact name of registrant as specified in its charter)



Delaware (State or other jurisdiction of incorporation or organization)	001-34046 (Commission File Number)	26-1075808 (IRS Employer Identification No.)

1201 Lake Robbins Drive The Woodlands, Texas 77380-1046 (Address of principal executive office) (Zip Code)

(832) 636-6000 (Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 1.01. Entry into a Material Definitive Agreement.

On August 9, 2018, Western Gas Partners, LP (the “ Partnership ”) completed the public offering of $400 million in aggregate principal amount of 4.75% senior notes due 2028 at a price to the public of 99.818% of their face value (the “ 2028 Notes ”) and $350 million in aggregate principal amount of 5.50% senior notes due 2048 at a price to the public of 98.912% of their face value (the “ 2048 Notes ” and, together with the 2028 Notes, the “ Notes ”).

The terms of the Notes are governed by the Indenture, dated as of May 18, 2011 (the “ Base Indenture ”), by and among the Partnership, the prior subsidiary guarantors party thereto and Wells Fargo Bank, National Association, as trustee (the “ Trustee ”), as supplemented by the Tenth Supplemental Indenture (the “ Supplemental Indenture ”), dated as of August 9, 2018, by and between the Partnership and the Trustee, setting forth the specific terms applicable to the Notes (the Base Indenture, as supplemented by the Supplemental Indenture, the “ Indenture ”). Interest on the Notes will accrue from August 9, 2018, and will be payable semi-annually on February 15 ^th and August 15 ^th of each year, with the initial interest payment being due on February 15, 2019.

The Partnership may redeem all or some of each series of the Notes, in whole or in part, at any time prior to their maturity at the applicable redemption price as set forth in the Indenture. The Notes rank equally in right of payment with all of the Partnership’s existing and future senior indebtedness and senior to any subordinated indebtedness that the Partnership may incur.

The Indenture contains covenants that will limit the ability of the Partnership and certain of its subsidiaries to create liens on its principal properties, engage in sale and leaseback transactions, merge or consolidate with another entity or sell, lease or transfer substantially all of its properties or assets to another entity. Initially, the Notes will not be guaranteed by any of the Partnership’s subsidiaries. In the future, however, if any of the Partnership’s subsidiaries guarantees the Partnership’s obligations under its revolving credit facility, then that subsidiary will, jointly and severally, fully and unconditionally guarantee the Partnership’s payment obligations under the Notes so long as such subsidiary has any guarantee obligation under the Partnership’s revolving credit facility.

The Indenture also contains customary events of default, including, among other things, (i) default for 30 days in the payment when due of interest on the Notes; (ii) default in payment when due of principal of or premium, if any, on the Notes at maturity, upon redemption or otherwise; and (iii) certain events of bankruptcy or insolvency with respect to the Partnership. If an event of default occurs and is continuing with respect to any series of Notes, the Trustee or the holders of not less than 25% in principal amount of such series of outstanding Notes may declare the principal amount of such Notes and all accrued and unpaid interest to be due and payable. Upon such a declaration, such principal amount will become due and payable immediately. If an event of default relating to certain events of bankruptcy, insolvency or reorganization with respect to the Partnership occurs and is continuing, the principal amount of such Notes outstanding will become immediately due and payable without any declaration or other act on the part of the Trustee or any holders of such Notes.

Other material terms of the Notes, the Base Indenture and the Supplemental Indenture are described in the prospectus supplement relating to the Notes, dated August 7, 2018, as filed by the Partnership with the Securities and Exchange Commission on August 8, 2018. The foregoing description of the Supplemental Indenture is qualified in its entirety by reference to the full text of such Supplemental Indenture, a copy of which is filed herewith as Exhibit 4.1, and is incorporated herein by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The information regarding the Notes and the Indenture set forth in Item 1.01 of this report is incorporated by reference into this Item 2.03.

Item 8.01. Other Events.

On August 7, 2018, the Partnership, together with its general partner, entered into an Underwriting Agreement (the “ Underwriting Agreement ”) with Wells Fargo Securities, LLC, PNC Capital Markets LLC, RBC Capital Markets, LLC and US Bancorp Investments, Inc. as representatives of the several underwriters, relating to the public offering (the “ Offering ”) of the 2028 Notes at a price to the public of 99.818% of the face amount of the 2028 Notes and the 2048 Notes at a price to the public of 98.912% of the face amount of the 2048 Notes.

On August 9, 2018, the Partnership completed the Offering. The Partnership expects to use the net proceeds from the offering to repay its maturing 2.600% senior notes due 2018, repay amounts outstanding under its revolving credit facility, and for general partnership purposes, including to fund capital expenditures.

The Offering was made pursuant to the Partnership’s shelf registration statement on Form S-3 (File No. 333-214446), which became effective on November 4, 2016.

The Underwriting Agreement contains customary representations, warranties and agreements, conditions to closing, indemnification obligations, including for liabilities under the Securities Act of 1933, and termination provisions. The foregoing description of the Underwriting Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Underwriting Agreement, which is filed as Exhibit 1.1 hereto and incorporated by reference herein.

Relationships

From time to time, certain of the underwriters and their related entities have engaged, and may in the future engage, in commercial and investment banking transactions with the Partnership in the ordinary course of their business. They have received, and expect to receive, customary compensation and expense reimbursement for these commercial and investment banking transactions. In addition, affiliates of certain of the underwriters are holders of the 2018 notes or lenders under the Partnership’s revolving credit facility and, as such, will receive a portion of the proceeds from the offering pursuant to the repayment of such indebtedness.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits



Exhibit Number		Description of the Exhibit
1.1		Underwriting Agreement, dated August 7, 2018, by and among the Partnership and Western Gas Holdings, LLC, and Wells Fargo Securities, LLC, PNC Capital Markets LLC, RBC Capital Markets, LLC and US Bancorp Investments, Inc., as representatives of the several underwriters named therein.
4.1		Tenth Supplemental Indenture, dated as of August 9, 2018, by and between Western Gas Partners, LP, as Issuer, and Wells Fargo Bank, National Association, as Trustee.
4.2		Form of 4.75% Senior Notes due 2028 (included as Exhibit A-1 to Exhibit 4.1).
4.3		Form of 5.50% Senior Notes due 2048 (included as Exhibit A-2 to Exhibit 4.1).
5.1		Opinion of Vinson & Elkins L.L.P.
23.1		Consent of Vinson & Elkins L.L.P. (included in Exhibit 5.1).

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.



		WESTERN GAS PARTNERS, LP

		By:	Western Gas Holdings, LLC, its general partner


Dated:	August 9, 2018	By:	/s/ Philip H. Peacock
			Philip H. Peacock Senior Vice President, General Counsel and Corporate Secretary

Exhibit 1.1

WESTERN GAS PARTNERS, LP

$400,000,000 4.750% Senior Notes due 2028

$350,000,000 5.500% Senior Notes due 2048

UNDERWRITING AGREEMENT

August 7, 2018

Wells Fargo Securities, LLC

PNC Capital Markets LLC

RBC Capital Markets, LLC

U.S. Bancorp Investments, Inc.

as Representatives of the several Underwriters,

c/o Wells Fargo Securities, LLC

550 South Tryon Street

Charlotte, North Carolina 28202

c/o PNC Capital Markets LLC

The Tower at PNC Plaza

300 Fifth Ave, Floor 10

Pittsburgh, Pennsylvania 15222

c/o RBC Capital Markets, LLC

Brookfield Place

200 Vesey Street

New York, New York 10281

c/o U.S. Bancorp Investments, Inc.

214 N. Tryon St., 26th Floor

Charlotte, North Carolina 28202

Ladies and Gentlemen:

Western Gas Partners, LP, a Delaware limited partnership (the “ Partnership ”), proposes to issue and sell to the underwriters named in Schedule A annexed hereto (the “ Underwriters ”), for whom Wells Fargo Securities, LLC, PNC Capital Markets LLC, RBC Capital Markets, LLC and U.S. Bancorp Investments, Inc. are acting as representatives (in such capacity, the “ Representatives ”), $400,000,000 aggregate principal amount of its 4.750% Senior Notes due 2028 (the “ 2028 Notes ”) and $350,000,000 aggregate principal amount of its 5.500% Senior Notes due 2048 (the “ 2048 Notes ” and, together with the 2028 Notes, the “ Notes ”). The Notes will be issued under the Tenth Supplemental Indenture (the “ Supplemental Indenture ”), to be dated the Closing Date (as defined below), to that certain Indenture dated as of May 18, 2011 (the “ Base Indenture ” and as supplemented by the Supplemental Indenture,

the “ Indenture ”), between the Partnership and Wells Fargo Bank, National Association, as trustee (the “ Trustee ”).

This Agreement is to confirm the agreement among the Partnership and Western Gas Holdings, LLC, a Delaware limited liability company and general partner of the Partnership (the “ General Partner ” and, together with the Partnership, the “ Western Gas Parties ”), on the one hand, and the Underwriters, on the other hand, concerning the purchase of the Notes from the Partnership by the Underwriters. The Western Gas Parties and the direct and indirect subsidiaries of the Partnership listed on Schedule B hereto (the “ Operating Subsidiaries ”) are collectively referred to herein as the “ Partnership Entities .”

The Western Gas Parties and the Underwriters agree as follows:

1. Sale and Purchase . Upon the basis of the representations and warranties and subject to the terms and conditions set forth herein, the Partnership agrees to issue and sell to the respective Underwriters, the General Partner agrees to cause the Partnership to issue and sell to the respective Underwriters and each of the Underwriters, severally and not jointly, agrees to purchase from the Partnership, the principal amount of Notes set forth opposite the name of such Underwriter in Schedule A attached hereto, subject to adjustment in accordance with Section 8 hereof, at a purchase price equal to 99.168% of the principal amount of the 2028 Notes and 98.037% of the principal amount of the 2048 Notes, in each case plus accrued and unpaid interest, if any, from August 9, 2018 to the Closing Date.

2. Payment and Delivery . Payment of the purchase price for the Notes shall be made to the Partnership by Federal Funds wire transfer against electronic delivery of the Notes in book-entry form to the Representatives through the facilities of The Depository Trust Company (“ DTC ”) for the respective accounts of the Underwriters. Such payment and delivery shall be made at 9:00 A.M., Houston, Texas time, on August 9, 2018 (the “ Closing Date ”) (unless another time shall be agreed to by the Representatives and the Partnership or unless postponed in accordance with the provisions of Section 8 hereof). The time at which such payment and delivery are to be made is sometimes referred to herein as the “ time of purchase .” Delivery of the Notes shall be made in book-entry form through the Full Fast Program of the facilities of DTC unless the Underwriters shall otherwise instruct. Time shall be of the essence, and delivery at substantially the time and place specified pursuant to this Agreement is a further condition of the obligation of the Underwriters.

Delivery of the documents described in Section 6 hereof with respect to the purchase of the Notes shall be made at the offices of Vinson & Elkins L.L.P., 1001 Fannin St., Suite 2500, Houston, Texas 77002, at 9:00 A.M., Houston, Texas time, on the Closing Date.

3. Representations and Warranties of the Western Gas Parties . Each of the Western Gas Parties, jointly and severally, represents, warrants to and agrees with each of the Underwriters that:

(a) A registration statement on Form S-3 (File No. 333-214446) relating to the Notes (i) has been prepared by the Partnership in conformity with the requirements of the Securities Act of 1933, as amended (the “ Securities Act ”), and the rules and regulations (the “ Rules and Regulations ”) of the Securities and Exchange Commission (the “ Commission ”) thereunder; (ii) has been filed with the Commission under the Securities Act; and (iii) is effective under the

Securities Act. Copies of such registration statement and any amendment thereto have been delivered by the Partnership to the Representatives. As used in this Agreement:

(i) “ Applicable Time ” means 4:10 P.M. (New York City time) on the date of this Agreement;

(ii) “ Effective Date ” means any date as of which any part of such registration statement relating to the Notes became, or is deemed to have become, effective under the Securities Act in accordance with the Rules and Regulations;

(iii) “ Issuer Free Writing Prospectus ” means each “free writing prospectus” (as defined in Rule 405 of the Rules and Regulations) prepared by or on behalf of the Partnership or used or referred to by the Partnership in connection with the offering of the Notes;

(iv) “ Preliminary Prospectus ” means any preliminary prospectus relating to the Notes included in such registration statement or filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations, including any preliminary prospectus supplement thereto relating to the Notes;

(v) “ Pricing Disclosure Package ” means, as of the Applicable Time, the most recent Preliminary Prospectus, together with the information included on Schedule C-1 hereto and each Issuer Free Writing Prospectus filed or used by the Partnership on or before the Applicable Time, other than a road show that is an Issuer Free Writing Prospectus under Rule 433 of the Rules and Regulations;

(vi) “ Prospectus ” means the final prospectus relating to the Notes, including any prospectus supplement thereto relating to the Notes, as filed with the Commission pursuant to Rule 424(b) of the Rules and Regulations; and

(vii) “ Registration Statement ” means, collectively, the various parts of the registration statement referred to in this Section 3(a) , each as amended as of the Effective Date for such part, including any Preliminary Prospectus or the Prospectus and all exhibits to such registration statement.

Any reference to any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any documents incorporated by reference therein pursuant to Form S-3 under the Securities Act as of the date of such Preliminary Prospectus or the Prospectus, as the case may be. Any reference to the “ most recent Preliminary Prospectus ” shall be deemed to refer to the latest Preliminary Prospectus included in the Registration Statement or filed pursuant to Rule 424(b) prior to or on the date hereof (including, for purposes hereof, any documents incorporated by reference therein prior to the date hereof). Any reference to any amendment or supplement to any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include any document filed under the Securities Exchange Act of 1934, as amended (the “ Exchange Act ”), after the date of such Preliminary Prospectus or the Prospectus, as the case may be, and incorporated by reference in such Preliminary Prospectus or the Prospectus, as the case may

be; and any reference to any amendment to the Registration Statement shall be deemed to include any annual report of the Partnership on Form 10-K filed with the Commission pursuant to Section 13(a) or 15(d) of the Exchange Act after the Effective Date that is incorporated by reference in the Registration Statement. The Commission has not issued any order preventing or suspending the use of any Preliminary Prospectus or the Prospectus or suspending the effectiveness of the Registration Statement, and no proceeding or examination for such purpose has been instituted or threatened by the Commission.

(b) Status as “Well-Known Seasoned Issuer . ” The Partnership was (i) at the time of filing the Registration Statement, (ii) at the time of the most recent amendment thereto for the purposes of complying with Section 10(a)(3) of the Securities Act (whether such amendment was by post-effective amendment, incorporated report filed pursuant to Section 13 or 15(d) of the Exchange Act or form of prospectus) and (iii) at the time the Partnership or any person acting on its behalf (within the meaning, for this clause only, of Rule 163(c) of the Rules and Regulations) made any offer relating to the Notes in reliance on the exemption of Rule 163 of the Rules and Regulations, a “well-known seasoned issuer” (as defined in Rule 405 of the Rules and Regulations). The Registration Statement is an “automatic shelf registration statement” (as defined in Rule 405 of the Rules and Regulations) and was filed not earlier than the date that is three years prior to the Closing Date.

(c) Partnership Not an Ineligible Issuer . For purposes of firm commitment underwritten offerings contemplated under the Registration Statement, the Partnership was not at the time of the initial filing of the Registration Statement and at the earliest time thereafter that the Partnership or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the Rules and Regulations) of the Notes, is not on the date hereof and will not be at the time of purchase, an “ineligible issuer” (as defined in Rule 405 of the Rules and Regulations). The Partnership has been since the time of the initial filing of the Registration Statement and continues to be eligible to use Form S-3 for the offering of the Notes.

(d) Form of Documents . The Registration Statement conformed and will conform in all material respects on each Effective Date and at the time of purchase, and any amendment to the Registration Statement filed after the date hereof will conform in all material respects when filed, to the requirements of the Securities Act and the Rules and Regulations. The most recent Preliminary Prospectus conformed, and the Prospectus will conform, in all material respects when filed with the Commission pursuant to Rule 424(b) and at the time of purchase to the requirements of the Securities Act and the Rules and Regulations. The documents incorporated by reference in any Preliminary Prospectus or the Prospectus conformed, and any further documents so incorporated will conform, when filed with the Commission, in all material respects to the requirements of the Exchange Act or the Securities Act, as applicable, and the rules and regulations of the Commission thereunder.

(e) Registration Statement . The Registration Statement did not, as of each Effective Date, contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; provided that no representation or warranty is made as to information contained in or omitted from the

Registration Statement in reliance upon and in conformity with written information furnished to the Partnership through the Representatives by or on behalf of any Underwriter specifically for inclusion therein, which information is specified in Section 10 (the “ Underwriter Information ”).

(f) Prospectus . The Prospectus will not, as of its date and at the time of purchase, include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that no representation or warranty is made as to information included in or omitted from the Prospectus in reliance upon and in conformity with the Underwriter Information.

(g) Documents Incorporated by Reference . The documents incorporated by reference in the Registration Statement, any Preliminary Prospectus or the Prospectus did not, and any further documents filed and incorporated by reference therein will not, when filed with the Commission, include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(h) Pricing Disclosure Package . The Pricing Disclosure Package did not, as of the Applicable Time, include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that no representation or warranty is made as to information included in or omitted from the Pricing Disclosure Package in reliance upon and in conformity with the Underwriter Information.

(i) Issuer Free Writing Prospectus and Pricing Disclosure Package . Each Issuer Free Writing Prospectus (including, without limitation, any road show that is a free writing prospectus under Rule 433), when considered together with the Pricing Disclosure Package as of the Applicable Time, did not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(j) Each Issuer Free Writing Prospectus . Each Issuer Free Writing Prospectus conformed or will conform in all material respects to the requirements of the Securities Act and the Rules and Regulations on the date of first use, and the Partnership has complied with any filing requirements applicable to such Issuer Free Writing Prospectus pursuant to the Rules and Regulations. The Partnership has not made any offer relating to the Notes that would constitute an Issuer Free Writing Prospectus without the prior written consent of the Representatives, except as set forth on Schedule C-2 hereto (each a “ Permitted Free Writing Prospectus ”). The Partnership has retained in accordance with the Rules and Regulations all Issuer Free Writing Prospectuses that were not required to be filed pursuant to the Rules and Regulations (it being understood that, as of the date hereof, the Partnership has not retained any Issuer Free Writing Prospectus for the three-year period required thereby). Each Issuer Free Writing Prospectus does not and will not include any information that conflicts with the information contained in

the Registration Statement or the Pricing Disclosure Package, including any document incorporated therein by reference and any prospectus supplement deemed to be a part thereof that has not been superseded or modified.

(k) Formation of the Partnership Entities . Each of the Partnership Entities has been duly formed and is validly existing as a limited partnership or limited liability company, as the case may be, and is in good standing under the laws of the State of Delaware, the State of Texas, the State of Wyoming or the State of Colorado, as the case may be, with full limited partnership or limited liability company power and authority to own, lease and operate its properties and conduct its business as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus and (i) in the case of the Western Gas Parties, to execute and deliver this Agreement and consummate the transactions contemplated hereby, (ii) in the case of the Partnership, to issue, sell and deliver the Notes, and (iii) in the case of the General Partner, to act as the general partner of the Partnership.

(l) Foreign Qualification and Registration . Each of the Partnership Entities is duly qualified to do business as a foreign limited partnership or limited liability company, as the case may be, and is in good standing in each jurisdiction where the ownership or lease of its properties or the conduct of its business requires such qualification (as set forth in Schedule B hereto), except for any failures to be so qualified and in good standing that would not, individually or in the aggregate, (i) have a material adverse effect on the business, assets, condition (financial or otherwise), results of operations or prospects of the Partnership Entities taken as a whole (a “ Material Adverse Effect ”) or (ii) subject the limited partners of the Partnership to any material liability or disability.

(m) Ownership of the General Partner . Western Gas Equity Partners, LP, a Delaware limited partnership (“ WGP ”), is the sole member of the General Partner, with a 100% membership interest in the General Partner; such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of the General Partner, as in effect as of the date hereof and at the time of purchase (the “ General Partner LLC Agreement ”), and is fully paid (to the extent required by the General Partner LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware Limited Liability Company Act (the “ Delaware LLC Act ”)); and, other than as disclosed in WGP’s reports filed with the Commission pursuant to Section 13(a) or 15(d) of the Exchange Act; and WGP owns such membership interest free and clear of all liens, encumbrances, security interests, charges or claims (“ Liens ”).

(n) Ownership of General Partner Interest in the Partnership . The General Partner is the sole general partner of the Partnership, with a 1.5% general partner interest in the Partnership; such general partner interest has been duly authorized and validly issued in accordance with the agreement of limited partnership of the Partnership, as in effect as of the date hereof and at the time of purchase (the “ Partnership Agreement ”), and the General Partner owns such general partner interest free and clear of all Liens, except for restrictions on transferability contained in the Partnership Agreement or as otherwise described in the

Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus.

(o) Capitalization . As of the date hereof, there are 152,609,285 common units representing limited partner interests in the Partnership (the “ Common Units ”) outstanding; 13,778,265 Class C limited partner interests in the Partnership (the “ Class C units ”) outstanding; and no Series A Preferred Units (the “ Series A Preferred Units ”) outstanding. WGP owns 50,132,046 Common Units, Kerr-McGee Worldwide Corporation, a Delaware corporation (“ KWC ”), owns 449,129 Common Units and APC Midstream Holdings, LLC, a Delaware limited liability company (“ AMH ”), owns 1,562,251 Common Units and13,778,265 Class C units (such Common Units and Class C units owned by WGP, KWC and AMH being referred to herein as the “ Sponsor Units ”); and the General Partner owns 2,583,068 general partner units and all of the Incentive Distribution Rights (as defined in the Partnership Agreement). All of the Sponsor Units and the limited partner interests represented thereby and the Incentive Distribution Rights have been duly authorized and validly issued in accordance with the Partnership Agreement and are fully paid (to the extent required by the Partnership Agreement) and nonassessable (except as such nonassessability may be affected by (i) matters described in the Registration Statement, the Pricing Disclosure Package and the Prospectus and (ii) Sections 17-303, 17-607 and 17-804 of the Delaware Revised Uniform Limited Partnership Act (the “ Delaware LP Act ”)); and all of the Sponsor Units owned by WGP, KWC and AMH and the Incentive Distribution Rights owned by the General Partner are owned free and clear of all Liens, except with respect to the restrictions on transferability contained in the Partnership Agreement or as otherwise described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus.

(p) Ownership of Wholly Owned Operating Subsidiaries . The Partnership directly or indirectly owns all of the issued and outstanding partnership interests or membership interests, as applicable, in the Operating Subsidiaries other than Chipeta Processing LLC, a Delaware limited liability company (“ Chipeta ”), in each case free and clear of all Liens. The issued and outstanding partnership interests or membership interests, as applicable, of each Operating Subsidiary other than Chipeta have been duly authorized and validly issued in accordance with such Operating Subsidiary’s partnership agreement or limited liability company agreement, as applicable, each as in effect as of the date hereof and at the time of purchase (collectively, the “ Constituent Agreements ”), and are fully paid (to the extent required by the Constituent Agreements) and nonassessable (except as such nonassessability may be affected by Sections 17-303, 17-607 and 17-804 of the Delaware LP Act, Sections 18-607 and 18-804 of the Delaware LLC Act, Article 101.206 of the Texas Business Organizations Code, Sections 17-29-405 and 17-29-406 of the Wyoming Limited Liability Company Act and Section 7-80-606 of the Colorado Limited Liability Company Act, as applicable).

(q) Ownership of Chipeta . WGR Operating, LP, a Delaware limited partnership (the “ Operating Partnership ”), owns a 75.0% membership interest in Chipeta; such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Chipeta, as in effect as of the date hereof and at the time of purchase (the “ Chipeta LLC Agreement ”), and is fully paid (to the extent required by the Chipeta LLC

Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and the Operating Partnership owns such membership interest free and clear of all Liens.

(r) Ownership of Fort Union . Western Gas Wyoming, L.L.C., a Wyoming limited liability company (“ WGW ”), owns a 14.81% membership interest in Fort Union Gas Gathering, L.L.C., a Delaware limited liability company (“ Fort Union ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Fort Union, as in effect as of the date hereof and at the time of purchase (the “ Fort Union LLC Agreement ”), and is fully paid (to the extent required by the Fort Union LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and WGW owns such membership interest free and clear of all Liens.

(s) Ownership of White Cliffs . Anadarko Wattenberg Company, LLC, a Delaware limited liability company (“ AWC ”), owns a 10.0% membership interest in White Cliffs Pipeline, L.L.C., a Delaware limited liability company (“ White Cliffs ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of White Cliffs, as in effect as of the date hereof and at the time of purchase (the “ White Cliffs LLC Agreement ”), and is fully paid (to the extent required by the White Cliffs LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and AWC owns such membership interest free and clear of all Liens.

(t) Ownership of Rendezvous . Mountain Gas Resources LLC, a Delaware limited liability company (“ Mountain Gas ”), owns a 22.0% membership interest in Rendezvous Gas Services, L.L.C., a Wyoming limited liability company (“ Rendezvous ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Rendezvous, as in effect as of the date hereof and at the time of purchase (the “ Rendezvous LLC Agreement ”), and is fully paid (to the extent required by the Rendezvous LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 17-29-405 and 17-29-406 of the Wyoming Limited Liability Company Act); and Mountain Gas owns such membership interest free and clear of all Liens.

(u) Ownership of Enterprise . The Operating Partnership owns a 25.0% membership interest in Enterprise EF78 LLC, a Delaware limited liability company (“ Enterprise ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Enterprise, as in effect as of the date hereof and at the time of purchase (the “ Enterprise LLC Agreement ”), and is fully paid (to the extent required by the Enterprise LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and the Operating Partnership owns such membership interest free and clear of all Liens.

(v) Ownership of Front Range . The Operating Partnership owns a 33.33% membership interest in Front Range Pipeline LLC, a Delaware limited liability company (“ Front

Range ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Front Range, as in effect as of the date hereof and at the time of purchase (the “ Front Range LLC Agreement ”), and is fully paid (to the extent required by the Front Range LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and the Operating Partnership owns such membership interest free and clear of all Liens.

(w) Ownership of Express Gathering . The Operating Partnership owns a 20.0% membership interest in Texas Express Gathering LLC, a Delaware limited liability company (“ Express Gathering ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Express Gathering, as in effect as of the date hereof and at the time of purchase (the “ Express Gathering LLC Agreement ”), and is fully paid (to the extent required by the Express Gathering LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and the Operating Partnership owns such membership interest free and clear of all Liens.

(x) Ownership of Express Pipeline . The Operating Partnership owns a 20.0% membership interest in Texas Express Pipeline LLC, a Delaware limited liability company (“ Express Pipeline ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Express Pipeline, as in effect as of the date hereof and at the time of purchase (the “ Express Pipeline LLC Agreement ”), and is fully paid (to the extent required by the Express Pipeline LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and the Operating Partnership owns such membership interest free and clear of all Liens.

(y) Ownership of Whitethorn . The Operating Partnership owns a 20.0% membership interest in Whitethorn Pipeline Company LLC, a Texas limited liability company (“ Whitethorn ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Whitethorn , as in effect as of the date hereof and at the time of purchase (the “ Whitethorn LLC Agreement ”), and is fully paid (to the extent required by the Whitethorn LLC Agreement) and nonassessable (except as such nonassessability may be affected by Article 101.206 of the Texas Business Organizations Code); and the Operating Partnership owns such membership interest free and clear of all Liens.

(z) Ownership of Cactus II . The Operating Partnership owns a 15.0% membership interest in Cactus II Pipeline LLC, a Delaware limited liability company (“ Cactus II ”); such membership interest has been duly authorized and validly issued in accordance with the limited liability company agreement of Cactus II , as in effect as of the date hereof and at the time of purchase (the “ Cactus II LLC Agreement ”), and is fully paid (to the extent required by the Cactus II LLC Agreement) and nonassessable (except as such nonassessability may be affected by Sections 18-607 and 18-804 of the Delaware LLC Act); and the Operating Partnership owns such membership interest free and clear of all Liens.

(aa) No Other Subsidiaries . The Partnership has no other direct or indirect “subsidiaries” (as defined under the Securities Act) other than the Operating Subsidiaries. Other than its ownership interest in the Operating Subsidiaries, the Partnership does not own, and at the time of purchase will not own, directly or indirectly, any shares of stock, any other equity interests or any long-term debt securities of any corporation, partnership, limited liability company, joint venture, association or other entity, other than its interests in Fort Union, White Cliffs, Rendezvous, Enterprise, Front Range, Express Gathering, Express Pipeline, Whitethorn and Cactus II and the note issued by Anadarko Petroleum Corporation as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus. All equity interests in the Operating Subsidiaries have been issued in compliance with all applicable securities laws and were not issued in violation of any preemptive right, resale right, right of first refusal or similar right. No options, warrants or other rights to purchase, agreements or other obligations to issue or rights to convert any obligation into equity interests in any of the Operating Subsidiaries are outstanding.

(bb) Valid Issuance of the Notes . The Notes have been duly authorized and, when executed by the Partnership, authenticated by the Trustee in accordance with the Indenture, and delivered against payment of the purchase price for the Notes as provided in this Agreement, will constitute valid and legally binding obligations of the Partnership enforceable against the Partnership in accordance with their terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

(cc) Conformity of Indenture and Notes to Description . The Indenture and the Notes, when issued and delivered against payment therefor as provided herein and in the Indenture, will conform in all material respects to the descriptions thereof contained in the Registration Statement, the Pricing Disclosure Package and the Prospectus.

(dd) Authority and Authorization . The Partnership has all requisite power and authority under the Partnership Agreement and the Delaware LP Act to issue, sell and deliver the Notes, in accordance with and upon the terms and conditions set forth in this Agreement, the Partnership Agreement, the Indenture, the Registration Statement, the Pricing Disclosure Package and the Prospectus. At the time of purchase all limited partnership and limited liability company action, as the case may be, required to be taken by the Partnership Entities or any of their partners or members for the authorization, issuance, sale and delivery of the Notes and the consummation of the transactions contemplated by this Agreement and the Indenture shall have been validly taken.

(ee) Authorization, Execution and Delivery of this Agreement . This Agreement has been duly authorized, executed and delivered by each of the Western Gas Parties.

(ff) Authorization and Enforceability of the Indenture. The execution and delivery of, and the performance by the Partnership of its obligations under, the Indenture have been duly and validly authorized by the Partnership. The Indenture has been duly qualified under the Trust Indenture Act of 1939, as amended (the “ Trust Indenture Act ”), and, assuming due

authorization, execution and delivery of the Base Indenture and the Supplemental Indenture by the Trustee, and when the Supplemental Indenture has been duly executed and delivered by the Partnership, the Indenture will constitute a valid and legally binding agreement of the Partnership, enforceable against the Partnership in accordance with its terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

(gg) No Defaults . No Partnership Entity is in breach or violation of or in default under (nor has any event occurred which, with notice, lapse of time or both, would result in any breach or violation of, constitute a default under or give the holder of any indebtedness (or a person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a part of such indebtedness under) (i) its formation, governing or other organizational documents, (ii) any indenture, mortgage, deed of trust, bank loan, credit agreement or other evidence of indebtedness, or any license, lease, contract or other agreement or instrument to which it is a party or by which it or any of its properties may be bound or affected, (iii) any federal, state, local or foreign law, regulation or rule, (iv) any rule or regulation of any self-regulatory organization or other non-governmental regulatory authority (including, without limitation, the rules and regulations of the New York Stock Exchange (the “ NYSE ”)), or (v) any decree, judgment or order applicable to it or any of its properties, except in the case of clauses (ii) through (v) for any such breaches, violations or defaults that would not, individually or in the aggregate, have a Material Adverse Effect, affect the validity of the Notes or prevent or materially interfere with the consummation of the transactions contemplated by this Agreement, including the proposed offering of the Notes (the “ Offering ”).

(hh) No Conflicts . The execution, delivery and performance of this Agreement by the Western Gas Parties, the issuance and sale of the Notes by the Partnership, the execution, delivery and performance of the Indenture by the Partnership and the consummation of the transactions contemplated by this Agreement and the Indenture will not conflict with, result in any breach or violation of, constitute a default under (or constitute any event which, with notice, lapse of time or both, would result in any breach or violation of, constitute a default under or give the holder of any indebtedness (or a person acting on such holder’s behalf) the right to require the repurchase, redemption or repayment of all or a part of such indebtedness under), or result in the creation or imposition of a Lien on any property or assets of any Partnership Entity pursuant to (i) the formation, governing or other organizational documents of any of the Partnership Entities, (ii) any indenture, mortgage, deed of trust, bank loan, credit agreement or other evidence of indebtedness, or any license, lease, contract or other agreement or instrument to which any of the Partnership Entities is a party or by which any of the Partnership Entities or any of their respective properties may be bound or affected, (iii) any federal, state, local or foreign law, regulation or rule, (iv) any rule or regulation of any self-regulatory organization or other non-governmental regulatory authority (including, without limitation, the rules and regulations of the NYSE), or (v) any decree, judgment or order applicable to any of the Partnership Entities or any of their respective properties, except in the cases of clauses (ii) through (v) for any such conflicts, breaches, violations or defaults that would not, individually or in the aggregate, have

a Material Adverse Effect, affect the validity of the Notes or prevent or materially interfere with the consummation of the transactions contemplated by this Agreement, including the Offering.

(ii) No Consents . No approval, authorization, consent or order of or filing with any federal, state, local or foreign governmental or regulatory commission, board, body, authority or agency, or of or with any self-regulatory organization or other non-governmental regulatory authority (including, without limitation, the NYSE), or approval of the security holders of the Partnership Entities (each, a “ Consent ”), is required in connection with the issuance and sale of the Notes by the Partnership, the execution, delivery and performance of this Agreement and the Indenture by the Western Gas Parties party thereto, or the consummation by such Western Gas Parties of the transactions contemplated by this Agreement and the Indenture, other than (i) Consents required under the Securities Act, the Exchange Act, the Trust Indenture Act and state securities or Blue Sky laws in connection with the purchase and distribution of the Notes by the Underwriters, (ii) under the rules and regulations of the Financial Industry Regulatory Authority (“ FINRA ”), (iii) Consents that have been, or prior to the Closing Date will be, obtained and (iv) Consents that, if not obtained, would not, individually or in the aggregate, have a Material Adverse Effect.

(jj) No Preemptive Rights, Registration Rights or Options . Except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, there are no (i) preemptive rights or other rights to subscribe for or to purchase, nor any restriction upon the voting or transfer of, any equity securities of the Partnership or (ii) outstanding options or warrants to purchase any securities of the Partnership, in each case pursuant to any agreement or other instrument to which the Partnership is a party or by which the Partnership may be bound. Except for such rights that have been waived or as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, neither the filing of the Registration Statement nor the offering or sale of the Notes as contemplated by this Agreement gives rise to any rights for or relating to the registration of any securities of the Partnership.

(kk) Permits . Each of the Partnership Entities has all necessary licenses, authorizations, consents and approvals (each, a “ Permit ”) and has made all necessary filings required under any applicable law, regulation or rule, and has obtained all necessary Permits from other persons, in order to conduct its business, except for such Permits the absence or omission of which would not, individually or in the aggregate, result in a Material Adverse Effect; and no Partnership Entity is in violation of or default under, or has received notice of any proceedings relating to the revocation or modification of, any such Permit or any federal, state, local or foreign law, regulation or rule or any decree, order or judgment applicable to such Partnership Entity, except for any such violations, defaults, revocations or modifications that would not, individually or in the aggregate, have a Material Adverse Effect.

(ll) Disclosure of Certain Items . All legal or governmental proceedings, affiliate transactions, off-balance sheet transactions, contracts, licenses, agreements, properties, leases or documents of a character required to be described in or incorporated by reference into the Registration Statement, the Pricing Disclosure Package or the Prospectus or to be filed as an exhibit to the Registration Statement have been so described or filed as required; and the

statements included in the Registration Statement, the Pricing Disclosure Package and the Prospectus under the headings “Description of Notes,” “Description of Debt Securities,” “Certain U.S. Federal Income Tax Considerations” and “Underwriting,” insofar as they purport to summarize legal or governmental matters or proceedings or the terms of statutes, rules, regulations, agreements or documents, are fair and accurate summaries of such legal or governmental matters or proceedings, statutes, rules, regulations, agreements or documents.

(mm) Litigation . Except as described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus, there are no actions, suits, claims, investigations or proceedings pending or, to the Western Gas Parties’ knowledge, threatened or contemplated to which the Partnership Entities or any of their respective directors or officers is or would be a party or to which any of their respective properties is or would be subject at law or in equity, before or by any federal, state, local or foreign governmental or regulatory commission, board, body, authority or agency, or before or by any self-regulatory organization or other non-governmental regulatory authority (including, without limitation, the NYSE), except for any such actions, suits, claims, investigations or proceedings that would not, individually or in the aggregate, if resolved adversely to any Partnership Entity, have a Material Adverse Effect, affect the validity of the Notes or prevent or materially interfere with the consummation of the transactions contemplated by this Agreement, including the Offering.

(nn) Independent Registered Public Accounting Firm . KPMG LLP, which has audited the financial statements contained or incorporated by reference in the Registration Statement, the Pricing Disclosure Package and the Prospectus, is an independent registered public accounting firm with respect to the Partnership and the General Partner within the meaning of the Securities Act and the applicable rules and regulations thereunder adopted by the Commission and the Public Company Accounting Oversight Board (United States) (the “ PCAOB ”).

(oo) Financial Statements . The historical financial statements (including the related notes and supporting schedule) contained or incorporated by reference in the Registration Statement, the Pricing Disclosure Package and the Prospectus, (i) comply in all material respects with the applicable requirements under the Securities Act and the Exchange Act (except that certain supporting schedules are omitted), (ii) present fairly in all material respects the financial position, results of operations and cash flows of the entities purported to be shown thereby on the basis stated therein at the respective dates or for the respective periods, and (iii) have been prepared in accordance with accounting principles generally accepted in the United States of America (“ GAAP ”) consistently applied throughout the periods involved, except to the extent disclosed therein. The other financial information of the General Partner and the Partnership and its subsidiaries, including non-GAAP financial measures, if any, contained or incorporated by reference in the Registration Statement, the Pricing Disclosure Package and the Prospectus has been derived from the accounting records of the General Partner, the Partnership and its subsidiaries, and fairly presents the information purported to be shown thereby. Nothing has come to the attention of any of the Partnership Entities that has caused them to believe that the statistical and market-related data included in the Registration Statement, the Pricing Disclosure

Package and the Prospectus is not based on or derived from sources that are reliable and accurate in all material respects.

(pp) No Material Adverse Change . Subsequent to the respective dates as of which information is given in the Registration Statement, the Pricing Disclosure Package and the Prospectus, in each case excluding any amendments or supplements to the foregoing made after the execution of this Agreement, except as described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus, there has not been (i) any material adverse change, or any developments that are reasonably likely to result in, individually or in the aggregate, a material adverse change, in the business, assets, management, condition (financial or otherwise), prospects or results of operations of the Partnership Entities (taken as a whole), (ii) any transaction that is material to the Partnership Entities (taken as a whole), (iii) any obligation or liability, direct or contingent (including any off-balance sheet obligations), incurred by any Partnership Entity that is material to the Partnership Entities (taken as a whole), (iv) any material change in the capitalization, ownership or outstanding indebtedness of any Partnership Entity or (v) any dividend or distribution of any kind declared, paid or made on the security interests of any Partnership Entity.

(qq) Investment Company . None of the Partnership Entities is, and at no time during which a prospectus is required by the Securities Act to be delivered (whether physically or through compliance with Rule 172 under the Securities Act or any similar rule) in connection with any sale of the Notes will any of them be, nor, after giving effect to the Offering and the application of the proceeds therefrom, will any of them be, an “investment company” or an entity “controlled” by an “investment company,” as such terms are defined in the Investment Company Act of 1940, as amended (the “ Investment Company Act ”).

(rr) Title to Properties . The Partnership Entities have good and marketable title to all real property and good title to all personal property described in the Registration Statement, the Pricing Disclosure Package and the Prospectus as being owned by any of them, free and clear of all Liens, except for (i) Liens that do not materially affect the value of such property and do not materially interfere with the use made or proposed to be made of such property by the Partnership Entities and (ii) Liens described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus.

(ss) Rights-of-Way . Each Partnership Entity has such consents, easements, rights-of-way or licenses from any person (“ rights-of-way ”) as are necessary to enable it to conduct its business in the manner described in the Registration Statement, the Pricing Disclosure Package and the Prospectus, subject to such qualifications as may be set forth in the Registration Statement, the Pricing Disclosure Package or the Prospectus, except for (i) qualifications, reservations and encumbrances that would not, individually or in the aggregate, have a Material Adverse Effect and (ii) such rights-of-way the absence or omission of which would not, individually or in the aggregate, have a Material Adverse Effect; and, except as described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus or as would not interfere with the operations of the Partnership Entities as conducted on the date hereof to such a material extent that the Representatives could reasonably conclude

that proceeding with the Offering would be inadvisable, none of such rights-of-way contains any restriction that is materially burdensome to the Partnership Entities, taken as a whole.

(tt) Labor and Employment Matters . No Partnership Entity is engaged in any unfair labor practice, and no labor disputes with the employees of or seconded to any Partnership Entity exist or, to the knowledge of the Western Gas Parties, are imminent or threatened that would, individually or in the aggregate, have a Material Adverse Effect. To the knowledge of the Western Gas Parties: (i) there is (A) no unfair labor practice complaint pending or threatened against any Partnership Entity before the National Labor Relations Board, and no grievance or arbitration proceeding arising out of or under collective bargaining agreements pending or threatened, (B) no strike, labor dispute, slowdown or stoppage pending or threatened against any Partnership Entity and (C) no union representation dispute currently existing concerning the employees of or seconded to any Partnership Entity, (ii) no union organizing activities are currently taking place concerning the employees of or seconded to any Partnership Entity and (iii) there has been no violation of any federal, state, local or foreign law relating to discrimination in the hiring, promotion or pay of employees, any applicable wage or hour laws or any provision of the Employee Retirement Income Security Act of 1974, as amended (“ ERISA ”), or the rules and regulations promulgated thereunder concerning the employees of or seconded to any Partnership Entity.

(uu) Environmental Compliance . Except as described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus, (i) each Partnership Entity and each of the properties, assets and operations of the Partnership Entities is in compliance with any and all applicable federal, state, local or foreign laws, statutes, ordinances, rules, regulations, orders, decrees, judgments, injunctions, permits, licenses, authorizations or other binding requirements, or fundamental principles of common laws, relating to human health or safety (to the extent relating to exposure to Hazardous Materials, as defined below) or the protection, cleanup or restoration of the environment (including natural resources), including those relating to the distribution, processing, generation, treatment, storage, disposal, transportation, other handling or release or threatened release of Hazardous Materials (as defined below) (“ Environmental Laws ”), (ii) each Partnership Entity has timely applied for or received and, to the extent received, is in compliance with all permits, licenses, authorizations or other approvals required under Environmental Laws to conduct its business as it is currently being conducted, (iii) no Partnership Entity has received written notice of any, and to the knowledge of the Western Gas Parties, there are no events, conditions or activities that could reasonably be expected to form the basis for any, actual or potential liability under Environmental Laws for the investigation or remediation of any disposal or release of Hazardous Materials (as defined below), and (iv) no Partnership Entity is subject to any pending or, to the knowledge of the Western Gas Parties, threatened actions, suits, demands, orders or proceedings against any Partnership Entity relating to any Environmental Laws (collectively, “ Proceedings ”), except for any such (A) failures to comply with Environmental Laws or to timely apply for or receive, or, to the extent received, to comply with, permits, licenses, authorizations or other approvals required under Environmental Laws, (B) actual or potential liabilities under Environmental Laws or (C) Proceedings that would not, individually or in the aggregate, have a Material Adverse Effect. Except as described in the Registration Statement (excluding the

exhibits thereto), the Pricing Disclosure Package and the Prospectus, no Partnership Entity has entered into any settlement agreement relating to any alleged violation of any Environmental Law or any actual or alleged release or threatened release or cleanup at any location of any Hazardous Materials (as defined below), except for any such agreements that would not, individually or in the aggregate, have a Material Adverse Effect. Except as described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus, no Partnership Entity is currently named as a “potentially responsible party” under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended. As used herein, “ Hazardous Materials ” means any material (including, without limitation, pollutants, contaminants, hazardous or toxic substances or wastes) that is regulated by or may give rise to liability under any Environmental Law. The costs and liabilities associated with the effect of Environmental Laws on the Partnership Entities’ properties, assets and operations (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws, or any permit, license, authorization or approval, any related constraints on operating activities and any potential liabilities to third parties) would not, singly or in the aggregate, have a Material Adverse Effect, except as set forth in or contemplated in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus.

(vv) ERISA Compliance . None of the following events has occurred or exists with respect to any of the Partnership Entities: (i) a failure to fulfill the obligations, if any, under the minimum funding standards of Section 302 of ERISA, and the regulations and published interpretations thereunder with respect to any Plan (as defined below), determined without regard to any waiver of such obligations or extension of any amortization period; (ii) an audit or investigation by the Internal Revenue Service, the U.S. Department of Labor, the Pension Benefit Guaranty Corporation or any other federal or state governmental agency or any foreign regulatory agency with respect to the employment or compensation of employees of or seconded to the Partnership Entities that would have a Material Adverse Effect; or (iii) any breach of any contractual obligation, or any violation of law or applicable qualification standards, with respect to the employment or compensation of employees of or seconded to the Partnership Entities by any such Partnership Entity that would have a Material Adverse Effect. None of the following events has occurred or is reasonably likely to occur with respect to any of the Partnership Entities: (i) a material increase in the aggregate amount of contributions required to be made to all Plans in the current fiscal year compared to the amount of such contributions made by the Partnership Entities in the most recently completed fiscal year; (ii) a material increase in the Partnership Entities’ “accumulated post-retirement benefit obligations” (within the meaning of Statement of Financial Accounting Standards 106) compared to the amount of such obligations in the most recently completed fiscal year; (iii) any event or condition giving rise to a liability under Title IV of ERISA that would have a Material Adverse Effect; or (iv) the filing of a claim by one or more employees of, former employees of, or employees seconded to the Partnership Entities related to its or their employment that would have a Material Adverse Effect. For purposes of this paragraph, the term “ Plan ” means a plan (within the meaning of Section 3(3) of ERISA) subject to Title IV of ERISA with respect to which any Partnership Entity may have any liability.

(ww) Tax Returns . All tax returns required to be filed by the Partnership Entities have been timely filed, and all taxes and other assessments of a similar nature (whether imposed directly or through withholding) including any interest, additions to tax or penalties applicable thereto due or claimed to be due from such entities have been timely paid, other than those (i) that are being contested in good faith and for which adequate reserves have been provided or (ii) that, if not paid, would not, individually or in the aggregate, have a Material Adverse Effect.

(xx) Insurance . The Partnership Entities maintain insurance covering the properties, operations, personnel and businesses of the Partnership Entities as such Partnership Entities reasonably deem adequate; such insurance insures against losses and risks to an extent which is adequate, in accordance with customary industry practice, to protect the Partnership Entities and their respective businesses; all such insurance is fully in force on the date hereof and will be fully in force at the time of purchase; and the Partnership Entities have no reason to believe that they will not be able to renew such insurance as and when such insurance expires.

(yy) Third Party Defaults . To the knowledge of the Western Gas Parties, no third party to any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to or by which any of the Partnership Entities is a party or bound or to which their respective properties are subject is in breach, default or violation under any such agreement (and no event has occurred that, with notice or lapse of time or both, would constitute such an event), which breach, default or violation would have a Material Adverse Effect.

(zz) Internal Controls . The Partnership Entities maintain a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorization; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

(aaa) Disclosure Controls . The Partnership has established and will maintain and evaluate “disclosure controls and procedures” (as such term is defined in Rule 13a-15 and 15d-15 under the Exchange Act) and “internal control over financial reporting” (as such term is defined in Rule 13a-15 and 15d-15 under the Exchange Act); such disclosure controls and procedures are designed to ensure that material information relating to the Partnership is made known to the General Partner’s Chief Executive Officer and its Chief Financial Officer, and such disclosure controls and procedures are effective to perform the functions for which they were established; the Partnership’s independent auditors and the Audit Committee of the Board of Directors of the General Partner have been advised of (i) all significant deficiencies, if any, in the design or operation of internal control over financial reporting which could adversely affect the Partnership’s ability to record, process, summarize and report financial data and (ii) all fraud, if any, whether or not material, that involves management or other employees who have a role

in the Partnership’s internal control over financial reporting; all material weaknesses, if any, in the Partnership’s internal control over financial reporting have been identified to the Partnership’s independent auditors; and since the date of the most recent evaluation of such disclosure controls and procedures and internal control over financial reporting, except as described in the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2017, there have been no significant changes in the Partnership’s internal control over financial reporting or in other factors that could significantly affect internal controls, including any corrective actions with regard to significant deficiencies and material weaknesses.

(bbb) Sarbanes-Oxley . The Partnership Entities have taken all necessary action to ensure that, upon and at all times after the filing of the Registration Statement, the Partnership Entities and their respective officers and directors, in their capacities as such, were and will be in compliance in all material respects with the applicable provisions of the Sarbanes-Oxley Act of 2002 and the rules and regulations of the Commission and the NYSE promulgated thereunder.

(ccc) Foreign Corrupt Practices Act . No Partnership Entity nor, to the knowledge of the Western Gas Parties, any director, officer, agent, employee or affiliate of the Partnership Entities has made any payment of funds of the Partnership Entities or received or retained any funds in violation of any law, rule or regulation (including, without limitation, the Foreign Corrupt Practices Act of 1977), which payment, receipt or retention is of a character required to be disclosed in the Registration Statement, the Preliminary Prospectuses and the Prospectus.

(ddd) Money Laundering Laws . The operations of the Partnership Entities are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines issued, administered or enforced by any governmental agency (collectively, “ Money Laundering Laws ”); and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator or non-governmental authority involving the Partnership Entities with respect to Money Laundering Laws is pending or, to the knowledge of the Western Gas Parties, threatened.

(eee) OFAC . No Partnership Entity nor, to the knowledge of the Western Gas Parties, any director, officer, agent, employee or affiliate of the Partnership Entities is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“ OFAC ”); and the Partnership Entities will not directly or indirectly use the proceeds of the Offering, or lend, contribute or otherwise make available such proceeds to any other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

(fff) No Prohibition on Distributions . No Partnership Entity is currently prohibited, directly or indirectly, from making distributions with respect to its equity securities, from repaying to any other Partnership Entity any loans or advances or from transferring any property or assets to the Partnership or any other Partnership Entity, except pursuant to the Chipeta LLC

Agreement or as described in the Registration Statement (excluding the exhibits thereto), the Pricing Disclosure Package and the Prospectus.

(ggg) Related Party Transactions . No Partnership Entity has, directly or indirectly (i) extended credit, arranged to extend credit, or renewed any extension of credit, in the form of a personal loan, to or for any director or executive officer of the General Partner or its affiliates, or to or for any family member or affiliate of any director or executive officer of the General Partner or its affiliates or (ii) made any material modification to the term of any personal loan to any director or executive officer of the General Partner or its affiliates, or any family member or affiliate of any director or executive officer of the General Partner or its affiliates.

(hhh) Stabilization or Manipulation . None of the Partnership Entities or any of their “affiliates” (as such term is defined in Rule 405 of the Rules and Regulations) has taken, directly or indirectly, any action which has constituted, or that was designed or might reasonably be expected to cause or result in, the stabilization or manipulation of the price of any security of the Partnership to facilitate the sale or resale of the Notes.

(iii) FINRA Affiliations . To the knowledge of the Western Gas Parties, there are no affiliations or associations between (i) any member of FINRA and (ii) the Partnership, the General Partner or any of the General Partner’s officers or directors or any 5% or greater securityholder of the Partnership, except as described in the Registration Statement, the Pricing Disclosure Package and the Prospectus.

(jjj) No Distribution of Other Offering Materials . None of the Partnership Entities has distributed, nor will they distribute, prior to the later to occur of (i) the time of purchase, and (ii) the completion of the distribution of the Notes, any “prospectus” (as defined under the Securities Act) in connection with the offering and sale of the Notes other than the Registration Statement, the Pricing Disclosure Package and the Prospectus or other materials, if any, permitted by the Securities Act, including Rule 134 promulgated thereunder.

In addition, any certificate signed by an officer of any of the Partnership Entities and delivered to the Underwriters or counsel for the Underwriters in connection with the offering or sale of the Notes shall be deemed to be a representation and warranty by such Partnership Entity, as to matters covered thereby, to each Underwriter.

4. Certain Covenants of the Western Gas Parties . The Western Gas Parties, jointly and severally, hereby agree:

(a) Preparation of Prospectus and Registration Statement . (i) To prepare the Prospectus in a form approved by the Underwriters and to file such Prospectus pursuant to Rule 424(b) under the Securities Act not later than the Commission’s close of business on the second business day following the execution and delivery of this Agreement; (ii) to make no further amendment or any supplement to the Registration Statement or to the Prospectus except as permitted herein; (iii) to advise the Underwriters, promptly after either of them receives notice thereof, of the time when any amendment to the Registration Statement has been filed or becomes effective or any supplement to the Prospectus or any amended Prospectus has been filed and to

furnish the Underwriters with copies thereof; (iv) to advise the Underwriters promptly after either of them receives notice thereof of the issuance by the Commission of any stop order or of any order preventing or suspending the use of the Prospectus or any Issuer Free Writing Prospectus, of the suspension of the qualification of the Notes for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose or of any request by the Commission for the amending or supplementing of the Registration Statement, the Prospectus or any Issuer Free Writing Prospectus or for additional information; and (v) in the event of the issuance of any stop order or of any order preventing or suspending the use of the Prospectus or any Issuer Free Writing Prospectus or suspending any such qualification, to use promptly their best efforts to obtain its withdrawal.

(b) Copies of Registration Statements . To furnish promptly to the Underwriters and to counsel for the Underwriters, upon request, a signed copy or a conformed copy of the Registration Statement as originally filed with the Commission, and each amendment thereto filed with the Commission, including all consents and exhibits filed therewith.

(c) Exchange Act Reports . To file promptly all reports and any definitive proxy or information statements required to be filed by the Partnership with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act (“ Exchange Act Reports ”) subsequent to the date of the Prospectus and for so long as the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) of the Rules and Regulations) is required in connection with the offering or sale of the Notes.

(d) Copies of Documents to the Underwriters . To deliver promptly to the Underwriters such number of the following documents as the Underwriters shall reasonably request: (i) conformed copies of the Registration Statement as originally filed with the Commission and each amendment thereto (in each case excluding exhibits), (ii) each Preliminary Prospectus, the Prospectus and any amended or supplemented Prospectus, (iii) each Issuer Free Writing Prospectus and (iv) any document incorporated by reference in any Preliminary Prospectus or the Prospectus; and, if the delivery of a prospectus (or in lieu thereof, the notice referred to in Rule 173(a) of the Rules and Regulations) is required at any time after the date hereof in connection with the offering or sale of the Notes or any other securities relating thereto and if at such time any events shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) of the Rules and Regulations) is delivered, not misleading, or, if for any other reason it shall be necessary to amend or supplement the Prospectus (or in lieu thereof, the notice referred to in Rule 173(a) of the Rules and Regulations) or to file under the Exchange Act any document incorporated by reference in the Prospectus in order to comply with the Securities Act or the Exchange Act or with a request from the Commission, to notify the Underwriters immediately thereof and to promptly prepare and, subject to Section 4(e) hereof, file with the Commission an amended Prospectus or supplement to the Prospectus which will correct such statement or omission or effect such compliance.

(e) Filing of Amendment or Supplement. To file promptly with the Commission any amendment to the Registration Statement or the Prospectus, any supplement to the Prospectus or any new, replacement registration statement that may, in the judgment of the Partnership or the Underwriters, be required by the Securities Act or requested by the Commission. Prior to filing with the Commission any amendment to the Registration Statement, any supplement to the Prospectus or any new, replacement registration statement, any document incorporated by reference in the Prospectus or any Prospectus pursuant to Rule 424 of the Rules and Regulations, to furnish a copy thereof to the Underwriters and counsel for the Underwriters and not to file any such document to which the Underwriters shall reasonably object after having been given reasonable notice of the proposed filing thereof unless the Partnership is required by law to make such filing. The Partnership will furnish to the Underwriters such number of copies of such new registration statement, amendment or supplement as the Underwriters may reasonably request and use its commercially reasonable efforts to cause such new registration statement or amendment to be declared effective as soon as practicable. In any such case, the Partnership will promptly notify the Representatives of such filings and effectiveness.

(f) Reports to Security Holders . As soon as practicable after the time of purchase, to make generally available to the Partnership’s security holders an earnings statement of the Partnership and its subsidiaries (which need not be audited) complying with Section 11(a) of the Securities Act and the Rules and Regulations (including, at the option of the Partnership, Rule 158).

(g) Copies of Reports . For a period of two years following the date hereof, to furnish to the Underwriters copies of all materials furnished by the Partnership to its security holders and all reports and financial statements furnished by the Partnership to the Commission pursuant to the Exchange Act or any rule or regulation of the Commission thereunder, in each case to the extent that such materials, reports and financial statements are not publicly filed with the Commission.

(h) Blue Sky Laws . Promptly to take from time to time such actions as the Underwriters may reasonably request to qualify the Notes for offering and sale under the securities or Blue Sky laws of such jurisdictions as the Underwriters may designate and to continue such qualifications in effect for so long as required for the resale of the Notes; and to arrange for the determination of the eligibility for investment of the Notes under the laws of such jurisdictions as the Underwriters may reasonably request; provided that no Western Gas Party shall be obligated to qualify as a foreign entity in any jurisdiction in which it is not so qualified or to file a general consent to service of process in any jurisdiction.

(i) Application of Proceeds . To apply the net proceeds from the sale of the Notes as set forth in the Pricing Disclosure Package and the Prospectus.

(j) Investment Company . To take such steps as shall be necessary to ensure that no Western Gas Party shall become an “investment company” as defined in the Investment Company Act.

(k) Issuer Free Writing Prospectuses. Not to make any offer relating to the Notes that would constitute an Issuer Free Writing Prospectus without the prior written consent of the Representatives.

(l) Retention of Issuer Free Writing Prospectuses. To retain in accordance with the Rules and Regulations all Issuer Free Writing Prospectuses not required to be filed pursuant to the Rules and Regulations; and if at any time after the date hereof and prior to the time of purchase, any events shall have occurred as a result of which any Issuer Free Writing Prospectus, as then amended or supplemented, would conflict with the information in the Registration Statement, the most recent Preliminary Prospectus or the Prospectus or, when considered together with the most recent Preliminary Prospectus, would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or, if for any other reason it shall be necessary to amend or supplement any Issuer Free Writing Prospectus, to notify the Representatives and, upon their reasonable request or as required by the Rules and Regulations, to file such document and to prepare and furnish without charge to each Underwriter as many copies as the Representatives may from time to time reasonably request of an amended or supplemented Issuer Free Writing Prospectus that will correct such conflict, statement or omission.

(m) Stabilization . To not directly or indirectly take any action constituting, or designed to or which might reasonably be expected to cause or result in, the stabilization or manipulation of the price of any security of the Partnership to facilitate the sale or resale of the Notes.

(n) Covenant to Pay Costs . Whether or not the transactions contemplated by this Agreement are consummated or this Agreement is terminated, to pay all costs, expenses, fees and taxes in connection with (i) the preparation and filing of the Registration Statement, each Preliminary Prospectus, the Prospectus, each Permitted Free Writing Prospectus and any amendments or supplements thereto, and the printing and furnishing of copies of each thereof to the Underwriters, counsel for the Underwriters and dealers (including costs of mailing and shipment), (ii) the registration, issuance, sale and delivery of the Notes including any stock or transfer taxes and stamp or similar duties payable upon the sale, issuance or delivery of the Notes to the Underwriters, (iii) the producing, word processing and/or printing of this Agreement, any agreement among underwriters, any dealer agreements, any powers of attorney and any closing documents (including compilations thereof) and the reproduction and/or printing and furnishing of copies of each thereof to the Underwriters and (except closing documents) to dealers (including costs of mailing and shipment), (iv) the qualification of the Notes for offering and sale under state or foreign laws and the determination of their eligibility for investment under state or foreign law (including the legal fees and filing fees and other disbursements of counsel for the Underwriters) and the printing and furnishing of copies of any blue sky surveys or legal investment surveys to the Underwriters and to dealers, (v) the registration of the Notes under the Exchange Act, (vi) any filing for review of the public offering of the Notes by FINRA, but not including the legal fees and other disbursements of counsel to the Underwriters relating to FINRA matters, (vii) the fees and disbursements of the Trustee for the Notes, (viii) the costs

and expenses of the Western Gas Parties relating to presentations or meetings undertaken in connection with the marketing of the offering and sale of the Notes to prospective investors and the Underwriters’ sales forces, including, without limitation, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations, travel, lodging and other expenses incurred by the officers of the Western Gas Parties and any such consultants, and the cost of any aircraft chartered in connection with the road show, (ix) the costs and expenses of qualifying the Notes for inclusion in the book-entry settlement system of the DTC, (x) the preparation and filing of the Registration Statement, including any amendments thereto, and (xi) the performance of the Western Gas Parties’ other obligations hereunder.

5. Reimbursement of Underwriters’ Expenses . If the Notes are not delivered at the time of purchase for any reason other than the termination of this Agreement pursuant to the fifth paragraph of Section 8 hereof or the default by one or more of the Underwriters in its or their respective obligations hereunder, the Western Gas Parties, jointly and severally, shall, in addition to paying the amounts described in Section 4(n) hereof, reimburse the Underwriters for all of their out-of-pocket expenses, including the fees and disbursements of their counsel; provided , however , that if this agreement is terminated because of the occurrence of any event specified in clause (b) of the second paragraph of Section 7 (other than as specified in clause (b)(ii) thereof), the Western Gas Parties shall not be obligated to reimburse the Underwriters for any expenses specified in this Section 5 .

6. Conditions of Underwriters’ Obligations . The several obligations of the Underwriters hereunder are subject to the accuracy of the representations and warranties on the part of the Western Gas Parties on the date hereof, at the time of purchase to the performance by the Western Gas Parties of their obligations hereunder and to the following additional conditions precedent:

(a) The Prospectus shall have been timely filed with the Commission in accordance with Section 4(a) of this Agreement; no stop order suspending the effectiveness of the Registration Statement or preventing or suspending the use of the Prospectus or any Issuer Free Writing Prospectuses or any part thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; any request of the Commission for inclusion of additional information in the Registration Statement or the Prospectus or otherwise shall have been complied with to the reasonable satisfaction of the Underwriters; and the Commission shall not have notified the Partnership of any objection to the use of the form of the Registration Statement.

(b) The Registration Statement, or any amendment thereto, does not contain an untrue statement of a fact which, in the opinion of counsel for the Underwriters, is material, or does not omit to state any fact which, in the opinion of such counsel, is material and is required to be stated therein or in the documents incorporated by reference therein or is necessary to make the statements therein not misleading, and the Prospectus or the Pricing Disclosure Package, or any supplement thereto, do not include an untrue statement of a fact which, in the opinion of counsel for the Underwriters, is material, or do not omit to state any fact which, in the opinion of such counsel, is necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(c) All partnership and limited liability company proceedings and other legal matters incident to the authorization, execution and filing of the Registration Statement, any Preliminary Prospectus, the Prospectus, the Indenture and any Issuer Free Writing Prospectus, and all other legal matters relating to this Agreement and the transactions contemplated hereby shall be reasonably satisfactory in all material respects to counsel for the Underwriters, and the Partnership shall have furnished to such counsel all documents and information that they or their counsel may reasonably request to enable them to pass upon such matters.

(d) The Partnership shall have furnished to the Representatives at the time of purchase an opinion of Vinson & Elkins L.L.P., counsel for the Partnership, addressed to the Underwriters, and dated the time of purchase, with executed copies for each of the other Underwriters, in form and substance reasonably satisfactory to the Representatives, substantially in the form set forth in Exhibit A hereto.

(e) At the time of execution of this Agreement, the Underwriters shall have received from KPMG LLP a letter or letters, in form and substance satisfactory to the Underwriters, addressed to the Underwriters and dated the date hereof (i) confirming that they are an independent registered public accounting firm within the meaning of the Securities Act and are in compliance with the applicable rules and regulations thereunder adopted by the Commission and the PCAOB, and (ii) stating that, as of the date hereof (or, with respect to matters involving changes or developments since the respective dates as of which specified financial information is given in the Pricing Disclosure Package and the Prospectus, as of a date not more than five days prior to the date hereof), the conclusions and findings of such firm with respect to the financial information and other matters ordinarily covered by accountants’ “comfort letters” to underwriters in connection with registered public offerings.

(f) With respect to the letter or letters of KPMG referred to in the preceding paragraph and delivered to the Underwriters concurrently with the execution of this Agreement (the “ initial letters ”), such accounting firm shall have furnished to the Underwriters a letter (the “ bring-down letter ”) of KPMG, addressed to the Underwriters and dated the date of the time of purchase (i) confirming that they are an independent registered public accounting firm within the meaning of the Securities Act and are in compliance with the applicable rules and regulations thereunder adopted by the Commission and the PCAOB, (ii) stating that, as of the date of the bring-down letter (or, with respect to matters involving changes or developments since the respective dates as of which specified financial information is given in the Prospectus, as of a date not more than five days prior to the date of the bring-down letter), the conclusions and findings of such firm with respect to the financial information and other matters covered by the initial letters and (iii) confirming in all material respects the conclusions and findings set forth in the initial letters.

(g) The Representatives shall have received at the time of purchase the favorable opinion of Latham & Watkins LLP, counsel for the Underwriters, addressed to the Underwriters, and dated the time of purchase in form and substance reasonably satisfactory to the Representatives.

(h) Prior to and at the time of purchase, (i) no stop order with respect to the effectiveness of the Registration Statement shall have been issued under the Securities Act and no proceedings shall have been initiated under Section 8(d) or 8(e) of the Securities Act; (ii) neither the Registration Statement nor any amendment thereto shall contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; (iii) neither the most recent Preliminary Prospectus nor the Prospectus, and no amendment or supplement thereto, shall include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they are made, not misleading; (iv) neither the Pricing Disclosure Package nor any amendment or supplement thereto shall include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they are made, not misleading; and (v) no Permitted Free Writing Prospectus shall include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they are made, not misleading.

(i) Between the time of execution of this Agreement and the time of purchase, (i) no material adverse change, or any developments that are reasonably likely to result in, individually or in the aggregate, a material adverse change, in the business, assets, management, condition (financial or otherwise), prospects or results of operations of the Partnership Entities, taken as a whole, shall have occurred or become known and (ii) no transaction which is material and adverse to the Partnership Entities, taken as a whole, shall have been entered into by any of the Partnership Entities or become probable, the effect of which is, in the judgment of the Representatives, so material or adverse as to make it impracticable or inadvisable to proceed with the Offering or the delivery of the Notes as contemplated by the Prospectus.

(j) No action shall have been taken and no statute, rule, regulation or order shall have been enacted, adopted or issued by any governmental agency or body which would, as of the time of purchase, prevent the issuance or sale of the Notes; and no injunction, restraining order or order of any other nature by any federal or state court of competent jurisdiction shall have been issued as of the time of purchase which would prevent the issuance or sale of the Notes.

(k) The Partnership shall have delivered to the Representatives at the time of purchase a certificate of the Chief Executive Officer and Chief Financial Officer of the General Partner, dated the time of purchase, in the form attached as Exhibit B hereto.

(l) The Western Gas Parties shall have furnished to the Representatives such other documents and certificates as to the accuracy and completeness of any statement in the Registration Statement, any Preliminary Prospectus, the Prospectus or any Permitted Free Writing Prospectus as of the time of purchase as the Representatives may reasonably request.

7. Effective Date of Agreement; Termination . This Agreement shall become effective when the parties hereto have executed and delivered this Agreement.

The obligations of the several Underwriters hereunder shall be subject to termination in the absolute discretion of the Representatives, if (a) since the time of execution of this Agreement or the earlier respective dates as of which information is given in the Registration Statement, the Pricing Disclosure Package, the Prospectus and any Permitted Free Writing Prospectus, there has been any change, or any developments that are reasonably likely to result in, individually or in the aggregate, a material adverse change, in the business, assets, management, condition (financial or otherwise), prospects or results of operations of any Partnership Entity, the effect of which change or development on the Partnership Entities, taken as a whole, is, in the sole judgment of the Representatives, so material and adverse as to make it impractical or inadvisable to proceed with the Offering or the delivery of the Notes on the terms and in the manner contemplated in the Registration Statement, the Pricing Disclosure Package, the Prospectus and each Permitted Free Writing Prospectus, (b) since the time of execution of this Agreement, there shall have occurred (i) a suspension or material limitation in trading in securities generally on the NYSE or the NASDAQ; (ii) a suspension or material limitation in trading in the Partnership’s securities on the NYSE; (iii) a general moratorium on commercial banking activities declared by either federal or New York State authorities or a material disruption in commercial banking or securities settlement or clearance services in the United States; (iv) an outbreak or escalation of hostilities or acts of terrorism involving the United States or a declaration by the United States of a national emergency or war; or (v) any other calamity or crisis or any change in financial, political or economic conditions in the United States or elsewhere, and, in the case of clause (iv) or (v), the effect of any such event, in the sole judgment of the Representatives, makes it impractical or inadvisable to proceed with the Offering or the delivery of the Notes on the terms and in the manner contemplated in the Registration Statement, the Pricing Disclosure Package, the Prospectus and each Permitted Free Writing Prospectus, or (c) since the time of execution of this Agreement, there shall have occurred any downgrading in, or any notice or announcement shall have been given or made of (i) any intended or potential downgrading or (ii) any watch, review or possible change that does not indicate an affirmation or improvement in the rating accorded to, any securities of or guaranteed by any Partnership Entity by any “nationally recognized statistical rating organization,” as that term is defined in Section 3(a)(62) of the Exchange Act.

If the Representatives elect to terminate this Agreement as provided in this Section 7 , the Partnership and each other Underwriter shall be notified promptly in writing.

If the sale to the Underwriters of the Notes, as contemplated by this Agreement, is not carried out by the Underwriters for any reason permitted under this Agreement, or if such sale is not carried out because the Western Gas Parties shall be unable to comply with any of the terms of this Agreement, the Western Gas Parties shall not be under any obligation or liability under this Agreement (except to the extent provided in Sections 4(n) , 5 and 9 hereof), and the Underwriters shall be under no obligation or liability to the Western Gas Parties under this Agreement (except to the extent provided in Section 9 hereof) or to one another hereunder.

8. Increase in Underwriters’ Commitments . Subject to Sections 6 and 7 hereof, if any Underwriter shall default in its obligation to take up and pay for the Notes to be purchased by it hereunder (otherwise than for a failure of a condition set forth in Section 6 hereof or a reason sufficient to justify the termination of this Agreement under the provisions of Section 7 hereof) and if the aggregate principal amount of the Notes that all Underwriters so defaulting shall have agreed but failed to take up and pay

for does not exceed 10% of the aggregate principal amount of the Notes to be purchased on the Closing Date, the non-defaulting Underwriters (including the Underwriters, if any, substituted in the manner set forth below) shall take up and pay for (in addition to the aggregate principal amount of the Notes they are obligated to purchase pursuant to Section 1 hereof) the aggregate principal amount of the Notes agreed to be purchased by all such defaulting Underwriters, as hereinafter provided. Such Notes shall be taken up and paid for by such non-defaulting Underwriters in such amount or amounts as the Representatives may designate with the consent of each Underwriter so designated or, in the event no such designation is made, such Notes shall be taken up and paid for by all non-defaulting Underwriters pro rata in proportion to the aggregate principal amount of the Notes set forth opposite the names of such non-defaulting Underwriters in Schedule A .

Without relieving any defaulting Underwriter of its obligations hereunder, the Partnership agrees with the non-defaulting Underwriters that it will not sell any Notes hereunder unless all of the Notes are purchased by the Underwriters (or by substituted Underwriters selected by the Representatives with the approval of the Partnership or selected by the Partnership with the approval of the Representatives).

If a new Underwriter or Underwriters are substituted by the Underwriters or by the Partnership for a defaulting Underwriter or Underwriters in accordance with the foregoing provision, the Partnership or the Representatives shall have the right to postpone the time of purchase for a period not exceeding five business days in order that any necessary changes in the Registration Statement and the Prospectus and other documents may be effected.

The term “Underwriter” as used in this Agreement shall refer to and include any Underwriter substituted under this Section 8 with like effect as if such substituted Underwriter had originally been named in Schedule A hereto.

If the aggregate principal amount of the Notes that the defaulting Underwriter or Underwriters agreed to purchase exceeds 10% of the aggregate principal amount of the Notes, and if neither the non-defaulting Underwriters nor the Partnership shall make arrangements within the five business day period stated above for the purchase of all the Notes that the defaulting Underwriter or Underwriters agreed to purchase hereunder, this Agreement shall terminate without further act or deed and without any liability on the part of the Partnership to any Underwriter and without any liability on the part of any non-defaulting Underwriter to the Partnership. Nothing in this paragraph, and no action taken hereunder, shall relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

9. Indemnity and Contribution .

(a) Each of the Western Gas Parties, jointly and severally, agrees to indemnify, defend and hold harmless each Underwriter, its partners, directors, officers and agents, affiliates of such Underwriter who have, or who are alleged to have, participated in the distribution of the Notes as underwriters, any person who controls any Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, and the successors and assigns of all of the foregoing persons, from and against any loss, damage, expense, liability or claim (including the reasonable cost of investigation) which, jointly or severally, any such Underwriter or any such person may incur under the Securities

Act, the Exchange Act, the common law or otherwise, insofar as such loss, damage, expense, liability or claim arises out of or is based upon (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement (or in the Registration Statement as amended by any post-effective amendment thereof by the Partnership) or any omission or alleged omission to state a material fact required to be stated therein or necessary to make the statements therein not misleading, except insofar as any such loss, damage, expense, liability or claim arises out of or is based upon any untrue statement or alleged untrue statement of a material fact that is contained in, and that is in conformity with the Underwriter Information furnished in writing by or on behalf of such Underwriter through the Representatives to the Partnership expressly for use in, the Registration Statement or arises out of or is based upon any omission or alleged omission to state a material fact in the Registration Statement in connection with such information, which material fact was not contained in such information and which material fact was required to be stated in such Registration Statement or was necessary to make such information not misleading, (ii) any untrue statement or alleged untrue statement of a material fact included in any Preliminary Prospectus, the Pricing Disclosure Package, the Prospectus, in any Permitted Free Writing Prospectus, in any “issuer information” (as defined in Rule 433 under the Securities Act) of the Partnership or in any Prospectus together with any combination of one or more Permitted Free Writing Prospectuses, if any, or arises out of or is based upon any omission or alleged omission to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, except, with respect to such Preliminary Prospectus, Pricing Disclosure Package, Prospectus or Permitted Free Writing Prospectuses, insofar as any such loss, damage, expense, liability or claim arises out of or is based upon any untrue statement or alleged untrue statement of a material fact that is included in, and that is in conformity with the Underwriter Information furnished in writing by or on behalf of such Underwriter through the Representatives to the Partnership expressly for use in, such Preliminary Prospectus, Pricing Disclosure Package, Prospectus or Permitted Free Writing Prospectus or arises out of or is based upon any omission or alleged omission to state a material fact in such Preliminary Prospectus, Pricing Disclosure Package, Prospectus or Permitted Free Writing Prospectus in connection with such information, which material fact was not included in such information and which material fact was necessary in order to make the statements in such information, in the light of the circumstances under which they were made, not misleading, or (iii) any untrue statement or alleged untrue statement of a material fact included in any “road show” (as defined in Rule 433 under the Securities Act) not constituting an Issuer Free Writing Prospectus.

(b) Each Underwriter severally and not jointly agrees to indemnify, defend and hold harmless the Western Gas Parties, their directors, officers and agents, any person who controls the Western Gas Parties within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, and the successors and assigns of all of the foregoing persons, from and against any loss, damage, expense, liability or claim (including the reasonable cost of investigation) which, jointly or severally, the Western Gas Parties or any such person may incur under the Securities Act, the Exchange Act, the common law or otherwise, insofar as such loss, damage, expense, liability or claim arises out of or is based upon (i) any untrue statement or alleged untrue statement of a material fact that is contained in, and that is in conformity with the Underwriter Information furnished in writing by or on behalf of such Underwriter through the Representatives to the Partnership expressly for use in, the Registration Statement (or in the Registration Statement as amended by any post-effective amendment thereof by the Partnership),

or any omission or alleged omission to state a material fact in such Registration Statement in connection with such information, which material fact was not contained in such information and which material fact was required to be stated in such Registration Statement or was necessary to make such information not misleading or (ii) any untrue statement or alleged untrue statement of a material fact that is contained in, and that is in conformity with the Underwriter Information furnished in writing by or on behalf of such Underwriter through the Representatives to the Partnership expressly for use in, a Preliminary Prospectus, the Pricing Disclosure Package, the Prospectus or a Permitted Free Writing Prospectus, or any omission or alleged omission to state a material fact in such Preliminary Prospectus, Pricing Disclosure Package, Prospectus or Permitted Free Writing Prospectus in connection with such information, which material fact was not contained in such information and which material fact was necessary in order to make the statements in such information, in the light of the circumstances under which they were made, not misleading.

(c) If any action, suit or proceeding (each, a “ Proceeding ”) is brought against a person (an “ indemnified party ”) in respect of which indemnity may be sought against any of the Western Gas Parties or an Underwriter (as applicable, the “ indemnifying party ”) pursuant to subsection (a) or (b) of this Section 9 , such indemnified party shall promptly notify such indemnifying party in writing of the institution of such Proceeding and such indemnifying party shall assume the defense of such Proceeding, including the employment of counsel reasonably satisfactory to such indemnified party and payment of all fees and expenses; provided , however , that the failure to so notify such indemnifying party shall not relieve such indemnifying party from any liability which such indemnifying party may have to any indemnified party or otherwise. The indemnified party or parties shall have the right to employ its or their own counsel in any such case, but the fees and expenses of such counsel shall be at the expense of such indemnified party or parties unless the employment of such counsel shall have been authorized in writing by the indemnifying party in connection with the defense of such Proceeding or the indemnifying party shall not have, within a reasonable period of time in light of the circumstances, employed counsel to defend such Proceeding or such indemnified party or parties shall have reasonably concluded that there may be defenses available to it or them which are different from, additional to or in conflict with those available to such indemnifying party (in which case such indemnifying party shall not have the right to direct the defense of such Proceeding on behalf of the indemnified party or parties), in any of which events such fees and expenses shall be borne by such indemnifying party and paid as incurred (it being understood, however, that, except as provided in Section 9(c) , such indemnifying party shall not be liable for the expenses of more than one separate counsel (in addition to any local counsel) in any one Proceeding or series of related Proceedings in the same jurisdiction representing the indemnified parties who are parties to such Proceeding). The indemnifying party shall not be liable for any settlement of any Proceeding effected without its written consent but, if settled with its written consent, such indemnifying party agrees to indemnify and hold harmless the indemnified party or parties from and against any loss or liability by reason of such settlement. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by the second sentence of this Section 9(c) , then the indemnifying party agrees that it shall be liable for any settlement of any Proceeding effected without its written consent if (i) such settlement is entered into more than 60 business days after receipt by such indemnifying party of the aforesaid request, (ii) such indemnifying party shall not have fully reimbursed the indemnified party in accordance with such request prior to

the date of such settlement and (iii) such indemnified party shall have given the indemnifying party at least 30 days’ prior notice of its intention to settle. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened Proceeding in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party, unless such settlement includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such Proceeding and does not include an admission of fault or culpability or a failure to act by or on behalf of such indemnified party.

(d) If the indemnification provided for in this Section 9 is unavailable to an indemnified party under subsection (a) or (b) of this Section 9 or insufficient to hold an indemnified party harmless in respect of any losses, damages, expenses, liabilities or claims referred to therein, then each applicable indemnifying party shall contribute to the amount paid or payable by such indemnified party as a result of such losses, damages, expenses, liabilities or claims (i) in such proportion as is appropriate to reflect the relative benefits received by the Western Gas Parties on the one hand and the Underwriters on the other hand from the Offering or (ii) if the allocation provided by clause (i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause (i) above but also the relative fault of the Western Gas Parties on the one hand and of the Underwriters on the other in connection with the statements or omissions which resulted in such losses, damages, expenses, liabilities or claims, as well as any other relevant equitable considerations. The relative benefits received by the Western Gas Parties on the one hand and the Underwriters on the other shall be deemed to be in the same respective proportions as the total proceeds from the Offering (net of underwriting discounts and commissions but before deducting expenses) received by the Western Gas Parties, and the total underwriting discounts and commissions received by the Underwriters, bear to the aggregate public offering price of the Notes. The relative fault of the Western Gas Parties on the one hand and of the Underwriters on the other shall be determined by reference to, among other things, whether the untrue statement or alleged untrue statement of a material fact or omission or alleged omission relates to information supplied by the Western Gas Parties or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The amount paid or payable by a party as a result of the losses, damages, expenses, liabilities and claims referred to in this subsection shall be deemed to include any legal or other fees or expenses reasonably incurred by such party in connection with investigating, preparing to defend or defending any Proceeding.

(e) The Western Gas Parties and the Underwriters agree that it would not be just and equitable if contribution pursuant to this Section 9 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in subsection (d) above. Notwithstanding the provisions of this Section 9 , no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Notes underwritten by such Underwriter and distributed to the public were offered to the public exceeds the amount of any damage that such Underwriter has otherwise been required to pay by reason of such untrue statement or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not

guilty of such fraudulent misrepresentation. The Underwriters’ obligations to contribute pursuant to this Section 9 are several in proportion to their respective underwriting commitments and not joint.

(f) The indemnity and contribution agreements contained in this Section 9 and the covenants, warranties and representations of the Western Gas Parties contained in this Agreement shall remain in full force and effect regardless of any investigation made by or on behalf of any Underwriter, its partners, directors, officers or agents, any affiliate of such Underwriter who has, or who is alleged to have, participated in the distribution of the Notes as an underwriter, or any person who controls any Underwriter within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, or by or on behalf of the Western Gas Parties, their directors, officers or agents or any person who controls the Western Gas Parties within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act, and shall survive any termination of this Agreement or the issuance and delivery of the Notes. The Western Gas Parties and each Underwriter agree promptly to notify each other of the commencement of any Proceeding against it and, in the case of the Western Gas Parties, against any of their officers or directors in connection with the issuance and sale of the Notes, or in connection with the Registration Statement, the Pricing Disclosure Package, the Prospectus or any Permitted Free Writing Prospectus.

10. Information Furnished by the Underwriters . The statements relating to stabilization by the Underwriters appearing in the fifth and sixth paragraphs under the caption “Underwriting” in the Prospectus, constitute the only information furnished by or on behalf of the Underwriters, as such information is referred to in Sections 3 and 9 hereof.

11. Notices . All statements, requests, notices and agreements hereunder shall be in writing, and:

(a) if to the Underwriters, shall be delivered or sent by mail or facsimile transmission to (i) Wells Fargo Securities, LLC, 550 South Tryon Street, 5 ^th Floor, Charlotte, North Carolina 28202, Attention: Transaction Management, Facsimile: 704-410-0326, (ii) PNC Capital Markets LLC, The Tower at PNC Plaza, 300 Fifth Ave, Floor 10, Pittsburgh, Pennsylvania 15222, Attention: PNC Debt Capital Markets, Facsimile: 412-762-2760, (iii) RBC Capital Markets, LLC, Brookfield Place, 200 Vesey Street, New York, New York 10281, Attention: DCM Transaction Management, Facsimile: 212-658-6137 and (iv) U.S. Bancorp Investments, Inc., 214 N. Tryon Street, 26 ^th Floor, Charlotte, North Carolina 28202, Attention: High Grade Syndicate, Facsimile: 877-774-3462; and

(b) if to the Western Gas Parties, shall be delivered or sent by mail or facsimile transmission to the offices of the Partnership at 1201 Lake Robbins Drive, The Woodlands, Texas 77380, Attention: Benjamin M. Fink, Chief Executive Officer, Facsimile: (832) 636-9850.

12. Governing Law; Construction . This Agreement and any claim, counterclaim or dispute of any kind or nature whatsoever arising out of or in any way relating to this Agreement (“ Claim ”), directly or indirectly, shall be governed by, and construed in accordance with, the laws of the State of New York. The section headings in this Agreement have been inserted as a matter of convenience of reference and are not a part of this Agreement.

13. Submission to Jurisdiction . Except as set forth below, no Claim may be commenced, prosecuted or continued in any court other than the courts of the State of New York located in the City and County of New York or in the United States District Court for the Southern District of New York, which courts shall have jurisdiction over the adjudication of such matters, and the Western Gas Parties consent to the jurisdiction of such courts and personal service with respect thereto. The Western Gas Parties hereby consent to personal jurisdiction, service and venue in any court in which any Claim arising out of or in any way relating to this Agreement is brought by any third party against any Underwriter or any indemnified party. Each Underwriter and the Western Gas Parties (each on its own behalf and, to the extent permitted by applicable law, on behalf of its equity owners and affiliates) waive all right to trial by jury in any action, proceeding or counterclaim (whether based upon contract, tort or otherwise) in any way arising out of or relating to this Agreement. Each of the Western Gas Parties agrees that a final judgment in any such action, proceeding or counterclaim brought in any such court shall be conclusive and binding upon the Western Gas Parties and may be enforced in any other courts to the jurisdiction of which the Western Gas Parties are or may be subject, by suit upon such judgment.

14. Parties at Interest . The agreement set forth herein has been and is made solely for the benefit of the Underwriters and the Western Gas Parties and to the extent provided in Section 9 hereof the controlling persons, affiliates, partners, directors and officers referred to in such Section, and their respective successors, assigns, agents, heirs, personal representatives and executors and administrators. No other person, partnership, association or corporation (including a purchaser, as such purchaser, from any of the Underwriters) shall acquire or have any right under or by virtue of this Agreement.

15. No Fiduciary Relationship . The Western Gas Parties hereby acknowledge that the Underwriters are acting solely as underwriters in connection with the purchase and sale of the Partnership’s securities. The Western Gas Parties further acknowledge that the Underwriters are acting pursuant to a contractual relationship created solely by this Agreement entered into on an arm’s length basis, and in no event do the parties intend that the Underwriters act or be responsible as a fiduciary to the Partnership Entities, their management, security holders or creditors or any other person in connection with any activity that the Underwriters may undertake or have undertaken in furtherance of the purchase and sale of the Notes, either before or after the date hereof. The Underwriters hereby expressly disclaim any fiduciary or similar obligations to the Partnership Entities, either in connection with the transactions contemplated by this Agreement or any matters relating to such transactions, and each Western Gas Party hereby confirms its understanding and agreement to that effect. The Western Gas Parties and the Underwriters agree that they are each responsible for making their own independent judgments with respect to any such transactions and that any opinions or views expressed by the Underwriters to the Partnership Entities regarding such transactions, including, but not limited to, any opinions or views with respect to the price or market for the Partnership’s securities, do not constitute advice or recommendations to the Partnership Entities. Each Western Gas Party hereby waives and releases, to the fullest extent permitted by law, any claims that it may have against the Underwriters with respect to any breach or alleged breach of any fiduciary or similar duty to the Partnership Entities in connection with the transactions contemplated by this Agreement or any matters relating to such transactions.

16. Counterparts . This Agreement may be signed by the parties in one or more counterparts which together shall constitute one and the same agreement among the parties.

17. Successors and Assigns . This Agreement shall be binding upon the Underwriters, the Western Gas Parties, their respective successors and assigns and any successor or assign of any substantial portion of any of the Western Gas Parties’ or any of the Underwriters’ respective businesses and/or assets.

[ The Remainder of This Page Intentionally Left Blank; Signature Pages Follow ]

If the foregoing correctly sets forth the understanding among the Western Gas Parties and the several Underwriters, please so indicate in the space provided below for that purpose, whereupon this Agreement and your acceptance shall constitute a binding agreement between the Western Gas Parties and the Underwriters, severally.



Very truly yours,

WESTERN GAS HOLDINGS, LLC

By:	/s/ Jaime R. Casas
	Name:	Jaime R. Casas
	Title:	Senior Vice President, Chief Financial Officer and Treasurer



WESTERN GAS PARTNERS, LP

By:	Western Gas Holdings, LLC, its general partner

By:	/s/ Jaime R. Casas
	Name:	Jaime R. Casas
	Title:	Senior Vice President, Chief Financial Officer and Treasurer

[Signature Page to Underwriting Agreement]

Accepted and agreed to as of the date first above written, on behalf of itself and the other several Underwriters name in Schedule A .



Wells Fargo Securities, LLC

By:	/s/ Carolyn Hurley
	Name:	Carolyn Hurley
	Title:	Director



PNC Capital Markets LLC

By:	/s/ Rachel Chalich
	Name:	Rachel Chalich
	Title:	Vice President



RBC Capital Markets, LLC

By:	/s/ Scott G. Primrose
	Name:	Scott G. Primrose
	Title:	Authorized Signatory



U.S. Bancorp Investments, Inc.

By:	/s/ Phil Bennett
	Name:	Phil Bennett
	Title:	Managing Director

[Signature Page to Underwriting Agreement]

SCHEDULE A

Underwriters



Underwriter	Principal Amount of 2028 Notes		Principal Amount of 2048 Notes
Wells Fargo Securities, LLC		$56,000,000		$49,000,000
PNC Capital Markets LLC		$56,000,000		$49,000,000
RBC Capital Markets, LLC		$56,000,000		$49,000,000
U.S. Bancorp Investments, Inc.		$56,000,000		$49,000,000
Barclays Capital Inc.		$26,000,000		$22,750,000
BB&T Capital Markets, a division of BB&T Securities, LLC		$26,000,000		$22,750,000
BMO Capital Markets Corp.		$26,000,000		$22,750,000
Credit Suisse Securities (USA) LLC		$26,000,000		$22,750,000
Scotia Capital (USA) Inc.		$26,000,000		$22,750,000
Capital One Securities, Inc.		$12,000,000		$10,500,000
Morgan Stanley & Co. LLC		$12,000,000		$10,500,000
TD Securities (USA) LLC		$12,000,000		$10,500,000
SG Americas Securities, LLC		$10,000,000		$8,750,000
Total		$400,000,000		$350,000,000

Schedule A-1

SCHEDULE B

Jurisdictions of Foreign Qualifications



Partnership Entity		Jurisdictions of Foreign Qualification
Western Gas Holdings, LLC		Arizona, Colorado, Kansas, New Mexico, Oklahoma, Texas, Utah, Wyoming
Western Gas Partners, LP		Arizona, Colorado, Kansas, New Mexico, Oklahoma, Texas, Utah, Wyoming
Operating Subsidiaries
Western Gas Operating, LLC		Arizona, Colorado, Kansas, New Mexico, Oklahoma, Texas, Utah, Wyoming
WGR Operating, LP		Arizona, Colorado, Kansas, New Mexico, Oklahoma, Pennsylvania, Texas, Utah, Wyoming
Anadarko Gathering Company LLC		Kansas, Louisiana, Mississippi, Oklahoma, Texas, Utah
MIGC LLC		Colorado, Wyoming
Western Gas Wyoming, L.L.C.		None
Chipeta Processing LLC		Colorado, Utah
Kerr-McGee Gathering LLC		None
Anadarko Wattenberg Company, LLC		None
Mountain Gas Resources, LLC		Colorado, Texas, Utah, Wyoming
Mountain Gas Transportation LLC		Colorado, Wyoming
GNB NGL Pipeline LLC		Colorado, Utah
Overland Trail Transmission, LLC		Wyoming
DBM Crude Services, LLC		New Mexico, Texas
DBM Pipeline, LLC		New Mexico, Texas
DBM Water Services, LLC		Colorado, New Mexico, Texas
Delaware Basin Express, LLC		Texas
Delaware Basin Midstream, LLC		New Mexico, Texas
Delaware Basin JV Gathering LLC		Texas
Springfield Pipeline LLC		None

Schedule B-1

SCHEDULE C-1

Information Included in the Pricing Disclosure Package

WESTERN GAS PARTNERS, LP

Terms Applicable to the Senior Notes due 2028



Issuer:	Western Gas Partners, LP
Security Type:	Senior Unsecured Notes
Legal Format:	SEC Registered
Pricing Date:	August 7, 2018
Settlement Date (T+2):	August 9, 2018
Net Proceeds Before Expenses:	$396,672,000
Maturity Date:	August 15, 2028
Principal Amount:	$400,000,000
Benchmark Treasury:	2.875% due May 15, 2028
Benchmark Treasury Price / Yield:	99-05+ / 2.973%
Spread to Benchmark Treasury:	T+180 bps
Yield to Maturity:	4.773%
Coupon:	4.750%
Public Offering Price:	99.818% of the principal amount
Optional Redemption:	Redeemable at any time before May 15, 2028 in an amount equal to the principal amount plus a make-whole premium, using a discount rate of T + 30 bps, plus accrued and unpaid interest. Redeemable at any time on or after May 15, 2028 in an amount equal to the principal amount plus accrued and unpaid interest.
Interest Payment Dates:	February 15 and August 15, beginning on February 15, 2019
CUSIP / ISIN:	958254 AK0 / US958254AK08
Expected Ratings (Moody’s / S&P / Fitch):*	Ba1 / BBB- / BBB-
Joint Book-Running Managers:	Wells Fargo Securities, LLC PNC Capital Markets LLC RBC Capital Markets, LLC U.S. Bancorp Investments, Inc. Barclays Capital Inc. BB&T Capital Markets, a division of BB&T Securities, LLC BMO Capital Markets Corp. Credit Suisse Securities (USA) LLC Scotia Capital (USA) Inc.

Schedule C-1-1



Co-Managers:	Capital One Securities, Inc. Morgan Stanley & Co. LLC TD Securities (USA) LLC SG Americas Securities, LLC

Terms Applicable to the Senior Notes due 2048



Issuer:	Western Gas Partners, LP
Security Type:	Senior Unsecured Notes
Legal Format:	SEC Registered
Pricing Date:	August 7, 2018
Settlement Date (T+2):	August 9, 2018
Net Proceeds Before Expenses:	$343,129,500
Maturity Date:	August 15, 2048
Principal Amount:	$350,000,000
Benchmark Treasury:	3.000% due February 15, 2048
Benchmark Treasury Price / Yield:	97-19 / 3.125%
Spread to Benchmark Treasury:	T+245 bps
Yield to Maturity:	5.575%
Coupon:	5.500%
Public Offering Price:	98.912% of the principal amount
Optional Redemption:	Redeemable at any time before February 15, 2048 in an amount equal to the principal amount plus a make-whole premium, using a discount rate of T + 40 bps, plus accrued and unpaid interest. Redeemable at any time on or after February 15, 2048 in an amount equal to the principal amount plus accrued and unpaid interest.
Interest Payment Dates:	February 15 and August 15, beginning on February 15, 2019
CUSIP / ISIN:	958254 AL8 / US958254AL80
Expected Ratings (Moody’s / S&P / Fitch):*	Ba1 / BBB- / BBB-

Schedule C-1-2



Joint Book-Running Managers:	Wells Fargo Securities, LLC PNC Capital Markets LLC RBC Capital Markets, LLC U.S. Bancorp Investments, Inc. Barclays Capital Inc. BB&T Capital Markets, a division of BB&T Securities, LLC BMO Capital Markets Corp. Credit Suisse Securities (USA) LLC Scotia Capital (USA) Inc.
Co-Managers:	Capital One Securities, Inc. Morgan Stanley & Co. LLC TD Securities (USA) LLC SG Americas Securities, LLC

After giving effect to the issuance and sale of the notes and the application of the net proceeds as set forth under “Use of Proceeds,” as of August 7, 2018, we would have been able to incur $1.5 billion of indebtedness under our revolving credit facility.

_________________________________________

* Note: A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time.

The Issuer has filed a registration statement (including a prospectus) with the U.S. Securities and Exchange Commission (the “SEC”) for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the Issuer has filed with the SEC for more complete information about the Issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC web site at http://www.sec.gov. Alternatively, the Issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling: Wells Fargo Securities, LLC toll-free at 1-800-645-3751; PNC Capital Markets LLC toll-free at 1-855-881-0697; RBC Capital Markets, LLC toll-free at 1-866-375-6829; or U.S. Bancorp Investments, Inc. toll-free at 1-877-558-2607.

This Pricing Supplement is qualified in its entirety by reference to the related preliminary prospectus supplement dated August 7, 2018 (the “Preliminary Prospectus Supplement”). The information in this Pricing Supplement supplements the Preliminary Prospectus Supplement and supersedes the information in the Preliminary Prospectus Supplement to the extent inconsistent with the information in the Preliminary Prospectus Supplement.

Schedule C-1-3

SCHEDULE C-2

Permitted Free Writing Prospectus

Issuer Free Writing Prospectus included in the Pricing Disclosure Package: Term sheet, dated August 7, 2018, substantially in the form of Schedule C-1.

Schedule C-2-1

EXHIBIT A

Form of Opinion of Vinson & Elkins L.L.P.


1.	Each Partnership Entity other than WGW and Kerr-McGee Gathering LLC (individually, a “ Covered Partnership Entity ”) is validly existing as a limited partnership or limited liability company, as the case may be, and is in good standing under the laws of the State of Delaware or, in the case of Springfield Pipeline LLC, the State of Texas.


2.	Each Covered Partnership Entity is duly qualified to do business as a foreign limited partnership or limited liability company, as the case may be, in, and is in good standing under the laws of, each jurisdiction so identified on Schedule B attached to this Agreement.

Each Covered Partnership Entity has all requisite entity power to own, lease and operate its respective properties and conduct its business, in each case in all material respects, as described in the Pricing Disclosure Package and the Prospectus. Each Western Gas Party has the entity power and authority necessary to (i) execute and deliver the Underwriting Agreement and, in the case of the Partnership, the Supplemental Indenture, and perform its obligations under the Underwriting Agreement and, in the case of the Partnership, the Indenture, (ii) in the case of the Partnership, issue, sell and deliver the Notes, and (iii) in the case of the General Partner has the limited liability company power and authority necessary to act as the general partner of the Partnership.


4.	The Underwriting Agreement has been duly authorized, executed and delivered by each of the Western Gas Parties.


5.	The Indenture has been duly qualified under the Trust Indenture Act, and each of the Base Indenture and the Supplemental Indenture has been duly authorized, executed and delivered by each Western Gas Party.


6.	The Notes have been duly authorized, executed and delivered by the Partnership.


7.	The Indenture constitutes a valid and legally binding agreement of the Partnership, enforceable against the Partnership in accordance with its terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

The Notes, when authenticated, issued and delivered in the manner provided for in the Indenture and delivered against payment of the purchase price for the Notes as provided in this Agreement, will constitute the valid and legally binding obligations of the Partnership enforceable against the Partnership in accordance with their terms, except as enforceability thereof may be limited by bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity.

Exhibit A-1

Anadarko indirectly owns all of the issued and outstanding membership interests in Western Gas Equity Holdings, LLC, a Delaware limited liability company and the sole general partner of WGP, free and clear of all Liens in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming Anadarko as debtor is on file in the office of the Secretary of State of the State of Delaware.

10.

WGP is the sole member of the General Partner, with a 100% membership interest in the General Partner; and WGP owns such membership interest free and clear of all Liens in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming WGP as debtor is on file in the office of the Secretary of State of the State of Delaware, except for any Liens established pursuant to that certain Revolving Credit Agreement, dated as of March 14, 2016, among WGP, as borrower, Wells Fargo Bank, National Association, as administrative agent, and the lenders and other agents party thereto.

11.

The General Partner is the sole general partner of the Partnership and owns of record a 1.5% general partner interest in the Partnership free and clear of all Liens (except for restrictions on transferability contained in the Partnership Agreement or as otherwise described in the Pricing Disclosure Package and the Prospectus) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming the General Partner as debtor is on file in the office of the Secretary of State of the State of Delaware.

12.

The Partnership directly or indirectly owns of record all of the issued and outstanding partnership interests and membership interests, as applicable, in the Operating Subsidiaries other than Chipeta free and clear of all Liens in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming the Partnership, the Operating Partnership or Western Gas Operating, LLC, a Delaware limited liability company, as debtor is on file in the office of the Secretary of State of the State of Delaware.

13.

The Operating Partnership owns of record a 75% membership interest in Chipeta free and clear of all Liens (except for restrictions on transferability contained in Chipeta’s limited liability company agreement) in respect of which a financing statement under the Uniform Commercial Code of the State of Delaware naming the Operating Partnership as debtor is on file in the office of the Secretary of State of the State of Delaware.

14.

Except for the General Partner’s preemptive right to maintain its general partner interest, which is contained in the Partnership Agreement, and except as described in the Pricing Disclosure Package or the Prospectus, (a) there are no preemptive rights or other rights to subscribe for or purchase, nor any restriction upon the voting or transfer of, any equity securities of the Partnership pursuant to or under the formation, governing or other organizational documents of the Partnership, any material agreement or other instrument filed as an exhibit to the Partnership’s Annual Report on Form 10-K for the year ended December 31, 2017 or any Quarterly Report on Form 10-Q or Current Report on Form 8-K filed subsequent to the Partnership’s most recently completed fiscal year (collectively, the “ Material Agreements ”), or any law, rule or regulation of the Delaware LP Act, the

Exhibit A-2

Delaware LLC Act, the laws of the State of Texas, the laws of the State of New York or federal law, and (b) the offering, issuance or sale of the Notes as contemplated by the Underwriting Agreement does not give rise under the formation, governing or other organizational documents of the Partnership or any Material Agreement to any rights for or relating to the registration of any securities of the Partnership, other than those that have been waived.

15.

The Registration Statement automatically became effective under the Act on November 4, 2016. To our knowledge, based solely upon our review of the stop orders contained on the SEC’s website located at http://www.sec.gov/litigation/stoporders.shtml on the Closing Date, no stop order suspending the effectiveness of the Registration Statement has been issued and no proceedings for that purpose have been instituted or threatened by the SEC. The filings of the Preliminary Prospectus and the Prospectus pursuant to Rule 424 under the Act were made in the manner and within the time period required by such Rule.

16.

No permit, consent, approval, authorization, order, registration, filing or qualification (“ Consent ”) under the Delaware LP Act, the Delaware LLC Act, the laws of the State of Texas, the laws of the State of New York or federal law is required in connection with the offering, issuance or sale of the Notes by the Partnership, or the execution, delivery and performance of the Underwriting Agreement and the Indenture by the Western Gas Parties party thereto, other than (a) such Consents required under state securities or “Blue Sky” laws, (b) such Consents that have been obtained or made and (c) filings with the SEC required in the performance by the Western Gas Parties of their obligations under Section 4 of the Underwriting Agreement.

17.

The offering, issuance and sale of the Notes by the Partnership to be sold by it pursuant to the Underwriting Agreement, the execution, delivery and performance of the Underwriting Agreement by the Western Gas Parties, the execution and delivery of the Supplemental Indenture and the performance of the Indenture by the Partnership, and the consummation by the Western Gas Parties of the transactions contemplated thereby do not and will not (A) conflict with or result in a breach or violation of any of the terms or provisions of, or constitute a default under, or result in the creation or imposition of any lien, charge or encumbrance upon any of the property or assets of the Covered Partnership Entities pursuant to any Material Agreement, (B) result in any violation of the provisions of any formation, governing or other organizational documents of any of the Covered Partnership Entities, as applicable, or (C) result in the violation of the Delaware LP Act, the Delaware LLC Act, the laws of the State of Texas, the laws of the State of New York or federal law (provided that such counsel need not express any opinion with respect to compliance with any state securities or federal or state antifraud law) or any judgment, order, rule or regulation of any court or arbitrator or governmental or regulatory authority known to us, except, in the case of clauses (A) and (C) above, for any such conflict, breach or violation that would not, individually or in the aggregate, have a Material Adverse Effect or a material adverse effect on the ability of any of the Western Gas Parties to consummate the transactions contemplated by the Underwriting Agreement and the Indenture.

Exhibit A-3


18.	The Partnership is not, and after giving effect to the Offering and the application of the proceeds therefrom as described in the Pricing Disclosure Package and the Prospectus, will not be, an “investment company” within the meaning of the Investment Company Act of 1940, as amended.


19.	The description of the Notes and the Indenture included in the Pricing Disclosure Package and the Prospectus under the headings “Description of Notes” and “Description of Debt Securities” are accurate in all material respects.

20.

The statements set forth in the preliminary prospectus supplement forming a part of the Pricing Disclosure Package and the prospectus supplement forming a part of the Prospectus under the caption “Certain U.S. Federal Income Tax Considerations,” insofar as they purport to constitute summaries of statutes, matters of law or legal conclusions, accurately summarize the matters described therein in all material respects.

In addition, such counsel shall state that they have participated in conferences with officers and other representatives of the Western Gas Parties, the independent registered public accountants of the Partnership, the Representatives and counsel for the Underwriters, at which the contents of the Registration Statement, the Pricing Disclosure Package and the Prospectus and related matters were discussed, and although such counsel has not independently verified, is not passing upon, and is not assuming any responsibility for the accuracy, completeness or fairness of the statements contained in, the Registration Statement, the Pricing Disclosure Package and the Prospectus (except to the extent specified in paragraphs (19) and (20) of the foregoing opinion), based on the foregoing, no facts have come to such counsel’s attention that lead such counsel to believe that:

(A) each of the Registration Statement, as of the date of the Underwriting Agreement, and the Preliminary Prospectus, as of the date of the Preliminary Prospectus, did not appear on its face to be appropriately responsive in all material respects with the requirements of the Securities Act and the rules and regulations thereunder, except that such counsel need not express any view as to the antifraud provisions of the U.S. federal securities laws and the rules and regulations promulgated under such provisions,

(B) the Registration Statement, as of the latest Effective Date, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading,

(C) the Pricing Disclosure Package, as of the Applicable Time, included an untrue statement of a material fact or omitted to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or

(D) the Prospectus, as of its date and on the Closing Date, included or includes an untrue statement of a material fact or omitted or omits to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading;

Exhibit A-4

it being understood that such counsel expresses no statement or belief with respect to (i) the financial statements and related schedules, including the notes thereto and independent registered public accountants’ reports thereon, included or incorporated by reference in the Registration Statement, the Pricing Disclosure Package or the Prospectus, (ii) any other financial or accounting information included or incorporated by reference in or omitted from the Registration Statement, the Pricing Disclosure Package or the Prospectus and (iii) representations and warranties and other statements of fact included in the exhibits to the Registration Statement or any documents incorporated by reference.

In rendering such opinion, such counsel may (A) rely in respect of matters of fact, to the extent such counsel deems appropriate, upon representations of the Western Gas Parties set forth in this Agreement and upon certificates of officers and employees of the Partnership Entities and upon information obtained from public officials, (B) assume that all documents submitted to them as originals are authentic, that all copies submitted to them conform to the originals thereof, and that the signatures on all documents examined by them are genuine, (C) state that their opinion is limited to the Delaware LP Act, the Delaware LLC Act, the laws of the State of Texas, the contract laws of the State of New York or federal law, (D) with respect to the opinions expressed in paragraph (2) above as to the due qualification or registration as a foreign corporation, limited partnership or limited liability company, as the case may be, of each of the Partnership Entities, state that such opinions are based upon certificates or other statements of foreign qualification or registration provided by the Secretary of State of the states listed on Schedule B hereto (each of which shall be dated as of a recent date and shall be provided to the Underwriters or their counsel), and (E) state that they express no opinion with respect to (i) any permits to own or operate any real property or (ii) foreign, state or local taxes or tax statutes to which any of the limited partners of the Partnership or any of the members of the General Partner may be subject.

Exhibit A-5

EXHIBIT B

Officers’ Certificate of Partnership

August 9, 2018

Each of the undersigned, Benjamin M. Fink, President and Chief Executive Officer of Western Gas Holdings, LLC, a Delaware limited liability company (the “ General Partner ”), which is the general partner of Western Gas Partners, LP, a Delaware limited partnership (the “ Partnership ”), and Jaime R. Casas, Senior Vice President, Chief Financial Officer and Treasurer of the General Partner, on behalf of the Partnership, does hereby certify pursuant to Section 6(k) of that certain Underwriting Agreement dated August 7, 2018 (the “ Underwriting Agreement ”) among the General Partner and the Partnership and, on behalf of the several Underwriters named therein, Wells Fargo Securities, LLC, PNC Capital Markets LLC, RBC Capital Markets, LLC and U.S. Bancorp Investments, Inc., that as of the date first set forth above:

1. He has reviewed the Registration Statement, each Preliminary Prospectus, the Prospectus and each Permitted Free Writing Prospectus, if any.

2. The representations and warranties of the Western Gas Parties as set forth in the Underwriting Agreement are true and correct as of the date hereof and as if made on the date hereof.

3. The Western Gas Parties have performed all of their obligations under the Underwriting Agreement as are to be performed at or before the date hereof.

4. The conditions set forth in Section 6(i) of the Underwriting Agreement have been met.

5. From the time of execution of the Underwriting Agreement to and including the date hereof, no material adverse change, or any developments that are reasonably likely to result in, individually or in the aggregate, a material adverse change, in the business, assets, management, condition (financial or otherwise), prospects or results of operations of the Partnership Entities, taken as a whole, has or have occurred.

6. Each of (i) Latham & Watkins LLP and (ii) Vinson & Elkins L.L.P. is entitled to rely on this certificate in connection with the opinion such firm is rendering pursuant to Section 6 of the Underwriting Agreement.

Capitalized terms used herein without definition shall have the respective meanings ascribed to them in the Underwriting Agreement.

[ Signature page follows ]

IN WITNESS WHEREOF, the undersigned have hereunto set their hands on the date first set forth above.




	Name:	Benjamin M. Fink
	Title:	President and Chief Executive Officer




	Name:	Jaime R. Casas
	Title:	Senior Vice President, Chief Financial Officer and Treasurer

Exhibit 4.1

WESTERN GAS PARTNERS, LP,
as Issuer

$400,000,000 4.750% SENIOR NOTES DUE 2028

$350,000,000 5.500% SENIOR NOTES DUE 2048

TENTH

SUPPLEMENTAL

INDENTURE

Dated as of August 9, 2018

WELLS FARGO BANK, NATIONAL ASSOCIATION,
as Trustee

TABLE OF CONTENTS



ARTICLE I			1
	Section 1.01.	Establishment	1

ARTICLE II DEFINITIONS AND INCORPORATION BY REFERENCE			2
	Section 2.01.	Definitions	2
	Section 2.02.	Other Definitions	5

ARTICLE III THE NOTES			6
	Section 3.01.	Form	6
	Section 3.02.	Issuance of Additional Notes	6
	Section 3.03.	Global Security Legend	6

ARTICLE IV REDEMPTION AND PREPAYMENT			7
	Section 4.01.	Optional Redemption	7

ARTICLE V COVENANTS			8
	Section 5.01.	Limitations on Liens	8
	Section 5.02.	Restriction of Sale-Leaseback Transactions	10
	Section 5.03.	Reports	11
	Section 5.04.	Future Subsidiary Guarantors	11
	Section 5.05.	Consolidation, Merger, Conveyance or Transfer of Subsidiary Guarantors	11

ARTICLE VI SUCCESSORS			12
	Section 6.01.	Consolidation and Mergers of the Partnership	12

ARTICLE VII LEGAL DEFEASANCE AND COVENANT DEFEASANCE			13
	Section 7.01.	Covenant Defeasance	13

ARTICLE VIII FUTURE GUARANTEES			13
	Section 8.01.	Release of Guarantees	13

ARTICLE IX MISCELLANEOUS			13
	Section 9.01.	Integral Part	13
	Section 9.02.	Adoption, Ratification and Confirmation	13
	Section 9.03.	Counterparts	14
	Section 9.04.	The Trustee	14
	Section 9.05.	Governing Law	14



EXHIBIT A-1:	Form of Global Security – 4.750% Senior Notes due 2028
EXHIBIT A-2:	Form of Global Security – 5.500% Senior Notes due 2048
EXHIBIT B:	Form of Notation of Guarantee

-i-

TENTH SUPPLEMENTAL INDENTURE dated as of August 9, 2018 (this “Supplemental Indenture”) between WESTERN GAS PARTNERS, LP, a Delaware limited partnership (the “Partnership”), and WELLS FARGO BANK, NATIONAL ASSOCIATION, as trustee (the “Trustee”).

W I T N E S S E T H:

WHEREAS, the Partnership and certain subsidiaries of the Partnership have heretofore entered into an Indenture, dated as of May 18, 2011 (the “Base Indenture”), with Wells Fargo Bank, National Association, as trustee;

WHEREAS, the Base Indenture, as supplemented by this Supplemental Indenture, is herein called the “Indenture”;

WHEREAS, under the Base Indenture, one or more new series of Debt Securities may at any time be established by the Board of Directors of the general partner of the Partnership in accordance with the provisions of the Base Indenture and the form and terms of any such series may be established by a supplemental indenture executed by the Partnership and the Trustee;

WHEREAS, the Partnership proposes to create under the Indenture two new series of Debt Securities;

WHEREAS, additional Debt Securities of other series hereafter established, except as may be limited in the Base Indenture as at the time supplemented and modified, may be issued from time to time pursuant to the Base Indenture as at the time supplemented and modified; and

WHEREAS, all conditions necessary to authorize the execution and delivery of this Supplemental Indenture and to make it a valid and binding obligation of the Partnership have been done or performed.

NOW, THEREFORE, in consideration of the agreements and obligations set forth herein and for other good and valuable consideration, the sufficiency of which is hereby acknowledged, the parties hereto hereby agree as follows:

ARTICLE I

Section 1.01. Establishment . (a) There are hereby established two new series of Debt Securities to be issued under the Indenture, to be designated as (i) the Partnership’s 4.750% Senior Notes due 2028 (the “2028 Notes”) and (ii) the Partnership’s 5.500% Senior Notes due 2048 (the “2048 Notes” and, together with the 2028 Notes, the “Notes”).

(b) There are to be authenticated and delivered $400,000,000 aggregate principal amount of 2028 Notes and $350,000,000 aggregate principal amount of 2048 Notes on the date hereof, and from time to time thereafter there may be authenticated and delivered an unlimited principal amount of Additional Notes.

(c) The 2028 Notes and the 2048 Notes shall be issued initially in the form of Global Securities, in substantially the form set out in Exhibit A-1 and Exhibit A-2 hereto, respectively. The Depositary with respect to the Notes shall be The Depository Trust Company.

(d) Each Note shall be dated the date of authentication thereof and shall bear interest from the date of original issuance thereof or from the most recent date to which interest has been paid or duly provided for.

(e) If and to the extent that the provisions of the Base Indenture are duplicative of, or in contradiction with, the provisions of this Supplemental Indenture, the provisions of this Supplemental Indenture shall govern.

(f) Unless the context indicates otherwise, the word “will” expresses a command.

ARTICLE II

DEFINITIONS AND INCORPORATION BY REFERENCE

Section 2.01. Definitions . All capitalized terms used herein and not otherwise defined below shall have the meanings ascribed thereto in the Base Indenture. The following are additional definitions used in this Supplemental Indenture:

“Board Resolution” means a copy of a resolution certified by the Secretary or an Assistant Secretary of the applicable Person to have been duly adopted by the Board of Directors of such Person and to be in full force and effect on the date of such certification, and delivered to the Trustee.

“Comparable Treasury Issue” means the United States Treasury security selected by the Quotation Agent as having a maturity comparable to the remaining term of the Notes to be redeemed, calculated as if the maturity date of the Notes of such series were the applicable Par Call Date (the “Remaining Life”) that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the Remaining Life of such Notes; provided , however , that if no maturity is within three months before or after the applicable Par Call Date, yields for the two published maturities most closely corresponding to such United States Treasury security shall be determined and the Treasury Rate will be interpolated or extrapolated from those yields on a straight line basis rounding to the nearest month.

“Comparable Treasury Price” means, with respect to any redemption date for Notes, (1) the average of four Reference Treasury Dealer Quotations for such redemption date after excluding the highest and lowest of all of the Reference Treasury Dealer Quotations or (2) if the Quotation Agent obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such quotations.

“Consolidated Net Tangible Assets” means at any date of determination, the total amount of consolidated assets of the Partnership and its Subsidiaries after deducting therefrom (1) all current liabilities (excluding (a) any current liabilities that by their terms are extendable or renewable at

the option of the obligor thereon to a time more than 12 months after the time as of which the amount thereof is being computed and (b) current maturities of long-term debt), and (2) the value (net of any applicable reserves) of all goodwill, trade names, trademarks, patents and other like intangible assets, all as set forth, or on a pro forma basis would be set forth, on the consolidated balance sheet of the Partnership and its Subsidiaries for the most recently completed fiscal quarter, prepared in accordance with generally accepted accounting principles in the United States.

“Debt” of any Person means, without duplication, (1) all indebtedness of such Person for borrowed money (whether or not the recourse of the lender is to the whole of the assets of such Person or only to a portion thereof), (2) all obligations of such Person evidenced by bonds, debentures, notes or other similar instruments, (3) all obligations of such Person in respect of letters of credit or other similar instruments (or reimbursement obligations with respect thereto), other than standby letters of credit, performance bonds and other obligations issued by or for the account of such Person in the ordinary course of business, to the extent not drawn or, to the extent drawn, if such drawing is reimbursed not later than the third Business Day following demand for reimbursement, (4) all obligations of such Person to pay the deferred and unpaid purchase price of property or services, except trade payables and accrued expenses incurred in the ordinary course of business, (5) all capitalized lease obligations of such Person, (6) all Debt of others secured by a Lien on any asset of such Person, whether or not such Debt is assumed by such Person (provided that if the obligations so secured have not been assumed in full by such Person or are not otherwise such Person’s legal liability in full, then such obligations shall be deemed to be in an amount equal to the greater of (a) the lesser of (i) the full amount of such obligations and (ii) the fair market value of such assets, as determined in good faith by the Board of Directors of such Person, which determination shall be evidenced by a Board Resolution, and (b) the amount of obligations as have been assumed by such Person or which are otherwise such Person’s legal liability), and (7) all Debt of others (other than endorsements in the ordinary course of business) guaranteed by such Person to the extent of such guarantee.

“guarantee” means a guarantee other than by endorsement of negotiable instruments for collection in the ordinary course of business, direct or indirect, in any manner including, without limitation, by way of a pledge of assets or through letters of credit or reimbursement agreements in respect thereof, of all or any part of any Debt. When used as a verb, “guarantee” has a correlative meaning.

“Guarantee” means any guarantee by a Subsidiary Guarantor of the Partnership’s obligations under the Indenture and on the Notes.

“obligations” means any principal, premium, if any, interest (including interest accruing on or after the filing of any petition in bankruptcy or for reorganization, whether or not a claim for post-filing interest is allowed in such proceeding), penalties, fees, charges, expenses, indemnifications, reimbursement obligations, damages, guarantees, and other liabilities or amounts payable under the documentation governing any Debt or in respect thereto.

“Par Call Date” means May 15, 2028 for the 2028 Notes (three months prior to the maturity date thereof) or February 15, 2048 for the 2048 Notes (six months prior to the maturity date thereof).

“Person” means any individual, corporation, partnership, joint venture, joint stock company, association, trust, unincorporated organization, limited liability company, government or any agency or political subdivision thereof or any other entity.

“Primary Treasury Dealer” means a U.S. government securities dealer in The City of New York.

“Principal Property” means, whether currently owned or leased or subsequently acquired, any pipeline, gathering system, terminal, storage facility, processing plant or other plant or facility located in the United States of America or any territory or political subdivision thereof owned or leased by the Partnership or any of its Subsidiaries and used in the transportation, distribution, terminalling, gathering, treating, processing, marketing or storage of natural gas and natural gas liquids and propane except (1) any property or asset consisting of inventories, furniture, office fixtures and equipment (including data processing equipment), vehicles and equipment used on, or useful with, vehicles (but excluding vehicles that generate transportation revenues) and (2) any such property or asset, plant or terminal which, in the good faith opinion of the Board of Directors of the General Partner as evidenced by resolutions of the Board of Directors of the General Partner, is not material in relation to the activities of the Partnership and its Subsidiaries, taken as a whole.

“Principal Subsidiary” means any of the Partnership’s Subsidiaries that owns or leases, directly or indirectly, a Principal Property.

“Quotation Agent” means the Reference Treasury Dealer appointed by the Partnership.

“Reference Treasury Dealer” means each of (i) Wells Fargo Securities, LLC and RBC Capital Markets, LLC and their respective successors so long as it is a Primary Treasury Dealer at the relevant time and, if it is not then a Primary Treasury Dealer, then a Primary Treasury Dealer selected by it, and (ii) a Primary Treasury Dealer selected by each of PNC Capital Markets LLC and U.S. Bancorp Investments, Inc. or their respective successors; provided that if any of the foregoing shall not be a Primary Treasury Dealer at such time and shall fail to select a Primary Treasury Dealer, then the Partnership will substitute therefor another Primary Treasury Dealer.

“Reference Treasury Dealer Quotation” means, with respect to each Reference Treasury Dealer and any redemption date, the average, as determined by the Quotation Agent, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Quotation Agent by such Reference Treasury Dealer at 5:00 p.m., New York City time, on the third Business Day preceding the redemption date.

“Revolving Credit Facility” means the Third Amended and Restated Revolving Credit Agreement, dated as of February 15, 2018, among the Partnership, Wells Fargo Bank, National Association, as the administrative agent and the lenders party thereto, as amended, restated, refinanced, replaced or refunded from time to time.

“Sale-Leaseback Transaction” means the sale or transfer by the Partnership or any Principal Subsidiary of any Principal Property to a Person (other than the Partnership or a Principal Subsidiary)

and the taking back by the Partnership or any Principal Subsidiary, as the case may be, of a lease of such Principal Property.

“Subsidiary” means, as to any Person, (1) any corporation, association or other business entity (other than a partnership or limited liability company) of which more than 50% of the outstanding capital stock having ordinary voting power is at the time owned or controlled, directly or indirectly, by such Person or one or more of the other Subsidiaries of such Person or (2) any general or limited partnership or limited liability company, (a) the sole general partner or member of which is the Person or a Subsidiary of the Person or (b) if there is more than one general partner or member, either (i) the only managing general partners or managing members of such partnership or limited liability company are such Person or Subsidiaries of such Person or (ii) such Person owns or controls, directly or indirectly, a majority of the outstanding general partner interests, member interests or other voting equities of such partnership or limited liability company, respectively.

“Subsidiary Guarantors” means any Subsidiary of the Partnership that becomes a Subsidiary Guarantor in accordance with the provisions of the Indenture.

“Treasury Rate” means, with respect to any redemption date, the rate per year equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such redemption date. The Partnership shall calculate the Treasury Rate on the third Business Day preceding any redemption date and notify the Trustee in writing of the Treasury Rate prior to the redemption.

Section 2.02. Other Definitions .



Term				Defined in Section

“2028 Notes”				1.01(a)
“2048 Notes”				1.01(a)
“Additional Notes”				3.02
“Base Indenture”				Recitals
“Exchange Act”				5.03(a)
“Indenture”				Recitals
“Lien”				5.01
“Notes”				1.01(a)
“Partnership”				Preamble
"SEC"				5.03(a)
“Supplemental Indenture”				Preamble
“Trustee”				Preamble

ARTICLE III
THE NOTES

Section 3.01. Form . The Notes shall be issued initially in the form of Global Securities. The Notes will be issued in denominations of $2,000 and integral multiples of $1,000 in excess thereof. The Notes and Trustee’s certificate of authentication shall be substantially in the form of Exhibit A-1 hereto in the case of the 2028 Notes or Exhibit A-2 hereto in the case of the 2048 Notes, in each case the terms of which are incorporated in and made a part of this Supplemental Indenture, and the Partnership and the Trustee, by their execution and delivery of this Supplemental Indenture, expressly agree to such terms and provisions and to be bound thereby. To further evidence any future Guarantee that may be issued pursuant to Section 5.04 of this Supplemental Indenture, a notation relating to such Guarantee, substantially in the form attached hereto as Exhibit B, shall be endorsed on each Note authenticated and delivered by the Trustee and executed by either manual or facsimile signature of an officer of such Subsidiary Guarantor, or in the case of a Subsidiary Guarantor that is a limited partnership, an officer of the general partner of such Subsidiary Guarantor.

Section 3.02. Issuance of Additional Notes . The Partnership may, from time to time, without notice to or the consent of the Holders of either series of the Notes or the Trustee, increase the principal amount of either or both series of Notes under the Indenture and issue such increased principal amount (or any portion thereof), in which case any additional Notes (“Additional Notes”) so issued will have the same form and terms (other than the date of issuance, the price to the public and, under certain circumstances, the date from which interest thereon will begin to accrue and the initial interest payment date), and will carry the same right to receive accrued and unpaid interest, as the applicable Notes of such series previously issued, and such Additional Notes will form a single series with such Notes for all purposes under the Indenture.

Section 3.03. Global Security Legend . Each Global Security shall bear a legend in substantially the following form:

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), NEW YORK, NEW YORK, TO THE PARTNERSHIP OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE INDENTURE REFERRED TO HEREIN.

ARTICLE IV
REDEMPTION AND PREPAYMENT

Section 4.01. Optional Redemption .

(a) The Partnership may redeem the Notes of each series in whole or in part at any time before the applicable Par Call Date, at a redemption price equal to the greater of (1) 100% of the principal amount of the Notes of such series to be redeemed and (2) the sum of the present values of the remaining scheduled payments of principal and interest on such Notes that would have been due if such Notes matured on the applicable Par Call Date (exclusive of interest accrued to the redemption date) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 30 basis points (with respect to the 2028 Notes) or 40 basis points (with respect to the 2048 Notes), plus, in either case, accrued interest, if any, on the principal amount being redeemed to such redemption date. On or after the applicable Par Call Date, the applicable series of Notes will be redeemable and repayable, at the Partnership’s option, at any time in whole, or from time to time in part, at a price equal to 100% of the principal amount of the Notes of such series to be redeemed plus accrued interest on the Notes of such series to be redeemed to the date of redemption.

(b) If fewer than all of the Notes of either series are to be redeemed at any time, the Notes of such series will be selected for redemption by the Trustee on a pro rata basis, by lot or by such other method as the Trustee deems appropriate (or, in the case of Notes represented by a Note in global form, by such method as DTC may require); provided , that no partial redemption of any Note will occur if such redemption would reduce the principal amount of such Note to less than $2,000. Notices of redemption with respect to the Notes of either series shall be sent at least 15 but not more than 60 days before the redemption date to each holder of Notes of such series to be redeemed at its registered address.

(c) If any Note is to be redeemed in part only, the notice of redemption that relates to such Note shall state the portion of the principal amount thereof to be redeemed. A new Note in principal amount equal to the unredeemed portion thereof will be issued in the name of the holder thereof upon cancellation of the original Note. Notes called for redemption will become due on the date fixed for redemption. Unless the Partnership defaults in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the Notes or portions of the Notes called for redemption.

(d) The provisions of Article III of the Base Indenture in respect of the Notes shall apply to any optional redemption of the Notes except when such provisions conflict with the foregoing.

ARTICLE V
COVENANTS

The following covenants, in addition to the covenants set forth in Article IV of the Base Indenture, shall apply to the Notes:

Section 5.01. Limitation on Liens . While any of the Notes remain outstanding, the Partnership will not, and will not permit any of its Principal Subsidiaries to, create, or permit to be created or to exist, any mortgage, lien, pledge, security interest, charge, adverse claim, or other encumbrance (“Lien”) upon any Principal Property of the Partnership or any of its Principal Subsidiaries, or upon any equity interests of any Principal Subsidiary, whether such Principal Property is, or equity interests are, owned on or acquired after the date of the Indenture, to secure any Debt, unless the Notes then outstanding are equally and ratably secured by such Lien for so long as any such Debt is so secured, other than:

(a) purchase money mortgages, or other purchase money Liens of any kind upon property acquired by the Partnership or any Principal Subsidiary after the date of the Indenture, or Liens of any kind existing on any property or any equity interests at the time of the acquisition thereof (including Liens that exist on any property or any equity interests of a Person that is consolidated with or merged with or into the Partnership or any Principal Subsidiary or that transfers or leases all or substantially all of its properties or assets to the Partnership or any Principal Subsidiary), or conditional sales agreements or other title retention agreements and leases in the nature of title retention agreements with respect to any property hereafter acquired, so long as no such Lien shall extend to or cover any other property of the Partnership or such Principal Subsidiary;

(b) Liens upon any property of the Partnership or any Principal Subsidiary or any equity interests of any Principal Subsidiary existing as of the date of the initial issuance of the Notes or upon the property or any equity interests of any entity, which Liens existed at the time such entity became a Subsidiary of the Partnership;

(c) Liens for taxes or assessments or other governmental charges or levies relating to amounts that are not yet delinquent or are being contested in good faith;

(d) pledges or deposits to secure: (i) any governmental charges or levies; (ii) obligations under workers’ compensation laws, unemployment insurance and other social security legislation; (iii) performance in connection with bids, tenders, contracts (other than contracts for the payment of money) or leases to which the Partnership or any Principal Subsidiary is a party; (iv) public or statutory obligations of the Partnership or any Principal Subsidiary; and (v) surety, stay, appeal, indemnity, customs, performance or return-of-money bonds or pledges or deposits in lieu thereof;

(e) builders’, materialmen’s, mechanics’, carriers’, warehousemen’s, workers’, repairmen’s, operators’, landlords’ or other similar Liens, in the ordinary course of business;

(f) Liens created by or resulting from any litigation or proceeding that at the time is being contested in good faith by appropriate proceedings, including Liens relating to judgments thereunder as to which the Partnership or any Principal Subsidiary has not exhausted its appellate rights;

(g) Liens on deposits required by any Person with whom the Partnership or any Principal Subsidiary enters into forward contracts, futures contracts, swap agreements or other commodities contracts in the ordinary course of business and in accordance with established risk management policies and Liens in connection with leases (other than capital leases) made, or existing on property acquired, in the ordinary course of business;

(h) easements (including, without limitation, reciprocal easement agreements and utility agreements), zoning restrictions, rights-of-way, covenants, consents, reservations, encroachments, variations and other restrictions on the use of property or minor irregularities in title thereto, charges or encumbrances (whether or not recorded) affecting the use of real property and which are incidental to, and do not materially impair the use of such property in the operation of the business of the Partnership and its Subsidiaries, taken as a whole, or the value of such property for the purpose of such business;

(i) Liens in favor of the United States of America, any State, any foreign country or any department, agency or instrumentality or political subdivision of any such jurisdiction, to secure partial, progress, advance or other payments pursuant to any contract or statute or to secure any Debt incurred for the purpose of financing all or any part of the purchase price or the cost of constructing or improving the property subject to such Liens, including, without limitation, Liens to secure Debt of the pollution control or industrial revenue bond type;

(j) Liens of any kind upon any property acquired, constructed, developed or improved by the Partnership or any Principal Subsidiary (whether alone or in association with others) after the date of the Indenture that are created prior to, at the time of, or within 12 months after such acquisition (or in the case of property constructed, developed or improved, after the completion of such construction, development or improvement and commencement of full commercial operation of such property, whichever is later) to secure or provide for the payment of any part of the purchase price or cost thereof; provided that in the case of such construction, development or improvement the Liens shall not apply to any property theretofore owned by the Partnership or any Principal Subsidiary other than theretofore unimproved real property;

(k) Liens in favor of the Partnership, one or more Principal Subsidiaries, one or more wholly-owned Subsidiaries of the Partnership or any of the foregoing in combination;

(l) the replacement, extension or renewal (or successive replacements, extensions or renewals), as a whole or in part, of any Lien, or of any agreement, referred to in the clauses above, or the replacement, extension or renewal of the Debt secured thereby (not exceeding the principal amount of Debt secured thereby, other than to provide for the payment of any underwriting or other fees related to any such replacement, extension or renewal, as well as any premiums owed on and accrued and unpaid interest payable in connection with any such replacement, extension or renewal); provided that such replacement, extension or renewal is

limited to all or a part of the same property that secured the Lien replaced, extended or renewed (plus improvements thereon or additions or accessions thereto); or

(m) any Lien not excepted by the foregoing clauses; provided that immediately after the creation or assumption of such Lien the aggregate principal amount of Debt of the Partnership or any Principal Subsidiary secured by all Liens created or assumed under the provisions of this clause, together with all net sale proceeds from any Sale-Leaseback Transactions, subject to certain exceptions set forth in the Base Indenture or herein, shall not exceed an amount equal to 15% of the Consolidated Net Tangible Assets for the fiscal quarter that was most recently completed prior to the creation or assumption of such Lien.

Notwithstanding the foregoing, for purposes of making the calculation set forth in clause (m) of the preceding paragraph, with respect to any such secured Debt of a non-wholly-owned Principal Subsidiary of the Partnership with no recourse to the Partnership or any wholly-owned Principal Subsidiary thereof, only that portion of the aggregate principal amount of such secured Debt reflecting the Partnership’s pro rata ownership interest in such non-wholly-owned Principal Subsidiary shall be included in calculating compliance herewith.

Section 5.02. Limitation of Sale-Leaseback Transactions . While the Notes remain outstanding, the Partnership will not, and will not permit any of its Principal Subsidiaries to engage in a Sale-Leaseback Transaction, unless:

(a) the Sale-Leaseback Transaction occurs within one year from the date of acquisition of the relevant Principal Property or the date of the completion of construction or commencement of full operations on such Principal Property, whichever is later, and the Partnership has elected to designate, as a credit against (but not exceeding) the purchase price or cost of construction of such Principal Property, an amount equal to all or a portion of the net sale proceeds from such Sale-Leaseback Transaction (with any such amount not being so designated to be applied as set forth in clause (b) below);

(b) the Partnership or such Principal Subsidiary would be entitled to incur Debt secured by a Lien on the Principal Property subject to the Sale-Leaseback Transaction in a principal amount equal to or exceeding the net sale proceeds from such Sale-Leaseback Transaction without equally and ratably securing the Notes; or

(c) the Partnership or such Principal Subsidiary, within a 270-day period after such Sale-Leaseback Transaction, applies or causes to be applied an amount not less than the net sale proceeds from such Sale-Leaseback Transaction to (1) the prepayment, repayment, redemption or retirement of any unsubordinated Debt of the Partnership or any of its Subsidiaries (A) for borrowed money or (B) evidenced by bonds, debentures, notes or other similar instruments, or (2) invest in another Principal Property.

Section 5.03. Reports . So long as any Notes are outstanding, the Partnership shall:

(a) during such time as it is subject to the reporting requirements of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), file with the Trustee, within

15 days after it files the same with the U.S. Securities and Exchange Commission (the “SEC”), copies of the annual reports and the information, documents and other reports which it is required to file with the SEC pursuant to the Exchange Act; and

(b) during such time as it is not subject to the reporting requirements of the Exchange Act, file with the Trustee, within 15 days after it would have been required to file the same with the SEC, financial statements, including any notes thereto (and with respect to annual reports, an auditors’ report by a firm of established national reputation) and a Management’s Discussion and Analysis of Financial Condition and Results of Operations, both comparable to what it would have been required to file with the SEC had it been subject to the reporting requirements of the Exchange Act.

With respect to the Notes, the provisions of this Section 5.03 shall replace and preempt the provisions of Section 4.05(a) of the Base Indenture in their entirety.

Section 5.04. Future Subsidiary Guarantors . As of the date of this Supplemental Indenture, the Notes shall not be guaranteed by any of the Partnership’s existing Subsidiaries. If, after the date of this Supplemental Indenture, any of the Partnership’s Subsidiaries guarantees, becomes a borrower or guarantor under, or grants any Lien to secure any obligations pursuant to, the Revolving Credit Facility, then the Partnership will cause such Subsidiary to become a Subsidiary Guarantor by executing a supplement to the Indenture and delivering such supplement to the Trustee promptly (but in any event, within ten Business Days of the date on which it guaranteed or incurred such obligations or granted such Lien, as the case may be).

Section 5.05. Consolidation, Merger, Conveyance or Transfer of Subsidiary Guarantors . No Subsidiary Guarantor shall consolidate with or merge with or into any other Person, or sell, assign, transfer, lease, convey or otherwise dispose of all or substantially all of its properties or assets and the properties or assets of its Subsidiaries (taken as a whole with the properties or assets of such Subsidiary Guarantor) to another Person in one or more related transactions unless:

(a) either: (i) in the case of a merger or consolidation, such Subsidiary Guarantor is the survivor; or (ii) the Person formed by or surviving any such consolidation or merger (if other than such Subsidiary Guarantor) or to which such sale, assignment, transfer, lease, conveyance or other disposition has been made, is a Person formed, organized or existing under the laws of the United States, any state thereof or the District of Columbia;

(b) the Person formed by or surviving any such consolidation or merger (if other than such Subsidiary Guarantor), or the Person to which such sale, assignment, transfer, lease, conveyance or other disposition has been made, expressly assumes all of such Subsidiary Guarantor’s obligations under its Guarantee and the Indenture pursuant to a supplemental indenture;

(c) the Subsidiary Guarantor or the successor Person delivers an Officers’ Certificate and Opinion of Counsel to the Trustee, each stating that such consolidation, merger, sale, assignment, transfer, lease, conveyance or other disposition and any supplemental indenture required in connection therewith comply with the Indenture and that all conditions precedent set forth in the Indenture have been complied with; and

(d) immediately after giving effect to the transaction, no Event of Default or default under the Indenture will have occurred and be continuing.

Upon the assumption of any Subsidiary Guarantor’s obligations under the Indenture by a successor, such Subsidiary Guarantor shall be discharged from all obligations under the Indenture.

ARTICLE VI
SUCCESSORS

With respect to the Notes, the provisions of this Article VI shall replace and preempt the provisions of Section 10.01 of the Base Indenture in their entirety.

Section 6.01. Consolidation and Mergers of the Partnership . The Partnership may not consolidate with or merge with or into any other Person, or sell, assign, transfer, lease, convey or otherwise dispose of all or substantially all of its properties or assets and the properties or assets of its Subsidiaries (taken as a whole with the properties or assets of the Partnership) to another Person in one or more related transactions unless:

(a) either (i) in the case of a merger or consolidation, the Partnership is the survivor; or (ii) the Person formed by or surviving any such consolidation or merger (if other than the Partnership) or to which such sale, assignment, transfer, lease, conveyance or other disposition has been made, is a Person formed, organized or existing under the laws of the United States, any state thereof or the District of Columbia;

(b) the Person formed by or surviving any such consolidation or merger (if other than the Partnership) or the Person to which such sale, assignment, transfer, lease, conveyance or other disposition has been made, expressly assumes all of the Partnership’s obligations under the Indenture, including the Partnership’s obligation to pay all principal of, premium, if any, and interest on, the Notes pursuant to the Indenture;

(c) the Partnership or the successor Person delivers an Officers’ Certificate and Opinion of Counsel to the Trustee, each stating that such consolidation, merger, sale, assignment, transfer, lease, conveyance or other disposition and any supplemental indenture required in connection therewith comply with the Indenture and that all conditions precedent set forth in the Indenture have been complied with;

(d) if the Partnership is not the survivor, each Subsidiary Guarantor delivers an Officers’ Certificate to the Trustee stating that its Guarantee will continue to apply to the Notes; and

(e) immediately after giving effect to the transaction, no Event of Default or default under the Indenture will have occurred and be continuing.

ARTICLE VII
LEGAL DEFEASANCE AND COVENANT DEFEASANCE

Section 7.01. Covenant Defeasance . If the Partnership effects a covenant defeasance of the Notes pursuant to Sections 11.02(b) and 11.03 of the Base Indenture, the Partnership shall cease to have any obligation to comply with the covenants set forth in Sections 5.01, 5.02, 5.04 and 5.05 hereof.

ARTICLE VIII
FUTURE GUARANTEES

In accordance with Article XIV of the Base Indenture and Section 5.04 of this Supplemental Indenture, under certain circumstances the Notes may be fully, unconditionally and absolutely guaranteed on a senior, unsecured basis by future Subsidiary Guarantors. With respect to the Notes, the provisions of this Article VIII shall replace and preempt the provisions of Sections 14.04(a) and 14.04(c) of the Base Indenture in their entirety.

Section 8.01. Release of Guarantees . The Guarantee of a Subsidiary Guarantor shall be released: (i) in connection with any sale or other disposition of all or substantially all of the properties or assets of, or all of the Partnership’s direct or indirect limited partnership, limited liability company or other equity interests in, such Subsidiary Guarantor (including by way of merger or consolidation) to a Person that is not (either before or after giving effect to such transaction) an Affiliate of the Partnership; (ii) upon the merger of such Subsidiary Guarantor into the Partnership or any other Subsidiary Guarantor or the liquidation or dissolution of such Subsidiary Guarantor; (iii) upon legal defeasance or covenant defeasance with respect to the Notes, as set forth in Sections 11.02(b) and 11.03 of the Base Indenture; or (iv) upon delivery of written notice to the Trustee of the release of all guarantees or other obligations of such Subsidiary Guarantor under the Revolving Credit Facility. If, at any time following any release of a Subsidiary Guarantor from its initial Guarantee of the Notes pursuant to clause (iv) in the preceding sentence, the Subsidiary Guarantor again incurs obligations under the Revolving Credit Facility, then the Partnership shall cause such Subsidiary Guarantor to again guarantee the Notes in accordance with the Indenture.

ARTICLE IX
MISCELLANEOUS

Section 9.01. Integral Part . This Supplemental Indenture constitutes an integral part of the Indenture.

Section 9.02. Adoption, Ratification and Confirmation . The Base Indenture, as supplemented and amended by this Supplemental Indenture, is in all respects hereby adopted, ratified and confirmed.

Section 9.03. Counterparts . This Supplemental Indenture may be executed in any number of counterparts, each of which when so executed shall be deemed an original; and all such counterparts shall together constitute but one and the same instrument. Delivery of an executed counterpart of this Supplemental Indenture by facsimile or electronic transmission shall be equally as effective as delivery of an original executed counterpart of this Supplemental Indenture. Any party delivering an executed counterpart of this Supplemental Indenture by facsimile or electronic

transmission also shall deliver an original executed counterpart of this Supplemental Indenture, but the failure to deliver an original executed counterpart shall not affect the validity, enforceability and binding effect of this Supplemental Indenture.

Section 9.04. The Trustee . The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which are made solely by the Partnership.

Section 9.05. Governing Law . THIS SUPPLEMENTAL INDENTURE AND THE NOTES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

[Signatures on following pages]

IN WITNESS WHEREOF, the parties hereto have caused this Indenture to be duly executed, all as of the day and year first above written.



WESTERN GAS PARTNERS, LP

By:	Western Gas Holdings, LLC, its general partner

By:	/s/ Jaime R. Casas
	Name:	Jaime R. Casas
	Title:	Senior Vice President, Chief Financial Officer and Treasurer

[Signature Page to Tenth Supplemental Indenture]



WELLS FARGO BANK, NATIONAL ASSOCIATION,
AS TRUSTEE

By:	/s/ Patrick Giordano
	Name:	Patrick Giordano
	Title:	Vice President

[Signature Page to Tenth Supplemental Indenture]

EXHIBIT A-1

(Form of Face of Note)



CUSIP 958254 AK0				No. __
ISIN US958254AK08				$__________

WESTERN GAS PARTNERS, LP

4.750% Senior Notes due 2028

Western Gas Partners, LP, promises to pay to __________, or its registered assigns, the principal sum of _______________ Dollars [or such greater or lesser amount as may be endorsed on the Schedule attached hereto] ¹ on August 15, 2028.

Interest Payment Dates: February 15 and August 15

Record Dates: February 1 and August 1

¹ To be included only if the Note is issued in global form.



WESTERN GAS PARTNERS, LP

By:	Western Gas Holdings, LLC, its general partner

By:
	Name:	Jaime R. Casas
	Title:	Senior Vice President, Chief Financial Officer and Treasurer

TRUSTEE’S CERTIFICATE OF

AUTHENTICATION

This is one of the Debt Securities of the series designated therein referred to in the within-mentioned Indenture.



WELLS FARGO BANK, NATIONAL ASSOCIATION,
As Trustee

By:
	Name:	Patrick Giordano
	Title:	Vice President

Dated: _________

[Signature Page to Global Note]

(Form of Back of Note)

4.750% Senior Notes due 2028

[UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), NEW YORK, NEW YORK, TO THE PARTNERSHIP OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR’S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE INDENTURE REFERRED TO HEREIN. ] ²

Capitalized terms used herein shall have the meanings assigned to them in the Indenture referred to below unless otherwise indicated.

1. Interest . Western Gas Partners, LP, a Delaware limited partnership (the “Partnership”), promises to pay interest on the principal amount of this Note at 4.750% per annum from August 9, 2018 until maturity. The Partnership shall pay interest semi-annually on February 15 and August 15 of each such year, or if any such day is not a Business Day, on the next succeeding Business Day (each an “Interest Payment Date”). Interest on the Notes shall accrue from the most recent date to which interest has been paid or, if no interest has been paid, from the date of issuance. The first Interest Payment Date shall be February 15, 2019.

2. Method of Payment . The Partnership shall pay interest on the Notes (except defaulted interest) to the Persons who are registered Holders of Notes at the close of business on the February 1 or August 1 next preceding the Interest Payment Date, even if such Notes are canceled after such record date and on or before such Interest Payment Date, except as provided in Section 2.17 of the Base Indenture with respect to defaulted interest, and the Partnership shall pay principal (and premium, if any) of the Notes upon surrender thereof to the Trustee or a paying agent on or after the maturity date thereof. The Notes shall be payable as to principal, premium, if any, and interest at the office or agency of the Trustee maintained for such purpose within or without The City and State of New York, or, at the option of the Partnership, payment of interest may be made

² To be included only if the Note is issued in global form.

A-1-2

by check mailed to the Holders at their addresses set forth in the register of Holders, and provided that payment by wire transfer of immediately available funds shall be required with respect to principal of and interest and premium, if any, on, each Global Security and all other Notes the Holders of which shall have provided wire transfer instructions to an account in the United States to the Partnership or the paying agent on or prior to the applicable record date. Such payment shall be in such coin or currency of the United States of America as at the time of payment is legal tender for payment of public and private debts.

3. Paying Agent and Registrar . Initially, Wells Fargo Bank, National Association, the Trustee under the Indenture, shall act as paying agent and Registrar. The Partnership may change any paying agent or Registrar without notice to any Holder. The Partnership or any of its Subsidiaries may act in any such capacity.

4. Indenture . The Partnership issued the 4.750% Senior Notes due 2028 (the “Notes”) under an Indenture, dated as of May 18, 2011, by and among the Partnership, the former guarantors party thereto and the Trustee (the “Base Indenture”), as supplemented by the Tenth Supplemental Indenture, dated as of August 9, 2018, between the Partnership and the Trustee (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”). The terms of the Notes include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended (15 U.S. Code §§ 77aaa-77bbbb). The Notes are subject to all such terms, and Holders are referred to the Indenture and such Act for a statement of such terms. To the extent any provision of this Note conflicts with the express provisions of the Indenture, the provisions of the Indenture shall govern and be controlling. The Notes are obligations of the Partnership initially in aggregate principal amount of $400,000,000. The Partnership may issue an unlimited aggregate principal amount of Additional Notes under the Indenture. Any such Additional Notes that are actually issued shall be treated as issued and outstanding Notes (and as the same series (with identical terms other than with respect to the issue date, the date of first payment of interest, if applicable, and the payment of interest accruing prior to the issue date) as the initial Notes) for all purposes of the Indenture, including waivers, amendments, redemptions and offers to purchase.

5. Optional Redemption . The Partnership may redeem the Notes, in whole or in part, at any time before May 15, 2028 (the “Par Call Date”), at a redemption price equal to the greater of (1) 100% of the principal amount of the Notes to be redeemed and (2) the sum of the present values of the remaining scheduled payments of principal and interest on such Notes that would have been due if the Notes matured on the Par Call Date (exclusive of interest accrued to the redemption date) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 30 basis points, plus, in either case, accrued interest, if any, on the principal amount being redeemed to such redemption date. On or after the Par Call Date, the Notes will be redeemable and repayable, at the Partnership’s option, at any time in whole, or from time to time in part, at a price equal to 100% of the principal amount of the Notes to be redeemed plus accrued interest on the Notes to be redeemed to the date of redemption.

A-1-3

For purposes of determining any redemption price, the following definitions shall apply:

“Comparable Treasury Issue” means the United States Treasury security selected by the Quotation Agent as having a maturity comparable to the remaining term of the Notes to be redeemed, calculated as if the maturity date of the Notes were the Par Call Date (the “Remaining Life”) that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the Remaining Life of such Notes; provided , however , that if no maturity is within three months before or after the Par Call Date, yields for the two published maturities most closely corresponding to such United States Treasury security shall be determined and the Treasury Rate will be interpolated or extrapolated from those yields on a straight line basis rounding to the nearest month.

“Primary Treasury Dealer” means a U.S. government securities dealer in The City of New York.

“Quotation Agent” means the Reference Treasury Dealer appointed by the Partnership.

A-1-4

6. Notice of Redemption . Notice of redemption shall be sent at least 15 days but not more than 60 days before the redemption date to each Holder whose Notes are to be redeemed at its registered address. Unless the Partnership defaults in payment of the redemption price, on and after the redemption date interest ceases to accrue on Notes or portions thereof called for redemption.

7. Denominations, Transfer, Exchange . The Notes are in registered form without coupons in minimum denominations of $2,000 and integral multiples of $1,000 in excess thereof. The transfer of Notes may be registered and Notes may be exchanged as provided in the Indenture. The Registrar and the Trustee may require a Holder, among other things, to furnish appropriate endorsements and transfer documents and the Partnership may require a Holder to pay any taxes or other governmental charges required by law or permitted by the Indenture. The Partnership need not exchange or register the transfer of any Note or portion of a Note selected for redemption or repurchase, except for the unredeemed or unrepurchased portion of any Note being redeemed or repurchased in part. Also, the Partnership need not exchange or register the transfer of any Notes for a period of 15 days before a selection of Notes to be redeemed or repurchased or during the period between a record date and the corresponding Interest Payment Date.

8. Persons Deemed Owners . The registered Holder of a Note shall be treated as its owner for all purposes.

9. Amendment, Supplement and Waiver . Subject to certain exceptions set forth in the Base Indenture or herein, the Indenture or the Notes may be amended or supplemented with the consent of the Holders of a majority in aggregate principal amount of the then outstanding Notes, and any existing default or compliance with any provision of the Indenture or the Notes may be waived with the consent of the Holders of a majority in aggregate principal amount of the then outstanding Notes. Without the consent of any Holder of a Note, the Indenture or the Notes may be amended or supplemented for any of the purposes set forth in Section 9.01 of the Base Indenture (as amended by the Supplemental Indenture), including to cure any ambiguity, defect or inconsistency, to provide for the assumption of the Partnership’s obligations to Holders of the Notes in case of a merger or consolidation of the Partnership or sale of all or substantially all of the Partnership’s assets, to add or release Subsidiary Guarantors (or their successors) pursuant to the terms of the Indenture, to make any change that would provide any additional rights or benefits to the Holders of the Notes or that does not adversely affect the legal rights under the Indenture of any Holder of the Notes, to comply with the requirements of the U.S. Securities and Exchange Commission to permit the qualification of the Indenture under the Trust Indenture Act, to evidence or provide for the acceptance of appointment under the Indenture of a successor Trustee, to add any additional Events of Default, to secure the Notes or the Guarantees or to establish the form or terms of any other series of Debt Securities.

10. Defaults and Remedies . Events of Default with respect to the Notes include: (i) default for 30 days in the payment when due of interest on the Notes; (ii) default in payment when due of principal of or premium, if any, on the Notes at maturity, upon redemption or otherwise, (iii) failure by the Partnership or any Subsidiary Guarantor for 60 days after notice to comply with any of the other agreements in the Indenture; (iv) except as permitted by the Indenture, any Guarantee

A-1-5

shall cease for any reason to be in full force and effect (except as otherwise provided in the Indenture) or is declared null and void in a judicial proceeding or any Subsidiary Guarantor, or any Person acting on behalf of any Subsidiary Guarantor, shall deny or disaffirm its obligations under the Indenture or its Guarantee and (v) certain events of bankruptcy or insolvency with respect to the Partnership or any of the Subsidiary Guarantors. If any Event of Default occurs and is continuing, the Trustee or the Holders of at least 25% in aggregate principal amount of the then outstanding Notes may declare all the Notes to be due and payable. Notwithstanding the foregoing, in the case of an Event of Default arising from certain events of bankruptcy or insolvency of either the Partnership or a Subsidiary Guarantor, all outstanding Notes shall become due and payable without further action or notice. Holders may not enforce the Indenture or the Notes except as provided in the Indenture. Subject to certain limitations set forth in the Base Indenture or herein, Holders of a majority in aggregate principal amount of the then outstanding Notes may direct the Trustee in its exercise of any trust or power. If and so long as the board of directors, an executive committee of the board of directors or trust committee of responsible officers of the Trustee in good faith so determines, the Trustee may withhold from Holders of the Notes notice of any continuing Default (except a Default relating to the payment of principal, premium, if any, or interest) if it determines that withholding notice is in their interests. The Holders of a majority in aggregate principal amount of the Notes then outstanding by notice to the Trustee may on behalf of the Holders of all of the Notes waive any past Default or Event of Default and its consequences under the Indenture except a continuing Default or Event of Default in the payment of interest on, the principal of, or premium, if any, on the Notes or except as otherwise specified in Section 6.06 of the Base Indenture. The Partnership and the Subsidiary Guarantors are required to deliver to the Trustee annually a statement regarding compliance with the Indenture, and the Partnership is required upon becoming aware of any Default or Event of Default, to deliver to the Trustee a statement specifying such Default or Event of Default.

11. Trustee Dealings with the Partnership . The Trustee, in its individual or any other capacity, may make loans to, accept deposits from, and perform services for the Partnership or its Affiliates, and may otherwise deal with the Partnership or its Affiliates, as if it were not the Trustee.

12. No Recourse Against Others . The partners (other than the General Partner), directors, officers, employees, incorporators and members of each of the Partnership and any Subsidiary Guarantors, as such, shall have no liability for any obligations of the Subsidiary Guarantors or the Partnership under the Debt Securities, this Indenture or any Guarantee or for any claim based on, in respect of, or by reason of, such obligations or their creation. By accepting a Debt Security, each Holder shall waive and release all such liability. The waiver and release shall be part of the consideration for the issue of the Debt Securities.

13. Authentication . This Note shall not be valid until authenticated by the manual signature of the Trustee or an authenticating agent.

14. Abbreviations . Customary abbreviations may be used in the name of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the entireties), JT TEN (= joint tenants with right of survivorship and not as tenants in common), CUST (= Custodian), and U/G/M/A (= Uniform Gifts to Minors Act).

A-1-6

15. CUSIP and ISIN Numbers . Pursuant to a recommendation promulgated by the Committee on Uniform Security Identification Procedures, the Partnership has caused CUSIP and corresponding ISIN numbers to be printed on the Notes, and the Trustee may use CUSIP and corresponding ISIN numbers in notices of redemption as a convenience to Holders. No representation is made as to the accuracy of such numbers either as printed on the Notes or as contained in any notice of redemption and reliance may be placed only on the other identification numbers placed thereon.

The Partnership shall furnish to any Holder upon written request and without charge a copy of the Indenture. Requests may be made to:

Western Gas Partners, LP

1201 Lake Robbins Drive

The Woodlands, Texas 77380-1046

Telephone: (832) 636-6000

A-1-7

Assignment Form

To assign this Note, fill in the form below: (I) or (we) assign and transfer this Note to




(Insert assignee’s soc. sec. or tax I.D. no.)




(Print or type assignee’s name, address and zip code)

and irrevocably appoint
agent to transfer this Note on the books of the Partnership. The agent may substitute another to act for him.


Date:

	Your Signature:
		(Sign exactly as your name appears on the face of this Note)

Signature Guarantee:
	(Signature must be guaranteed by a financial institution that is a member of the Securities Transfer Agent Medallion Program (“STAMP”), the Stock Exchange Medallion Program (“SEMP”), the New York Stock Exchange, Inc. Medallion Signature Program (“MSP”) or such other signature guarantee program as may be determined by the Registrar in addition to, or in substitution for, STAMP, SEMP or MSP, all in accordance with the Securities Exchange Act of 1934, as amended.)

A-1-8

SCHEDULE OF INCREASES OR DECREASES IN THE GLOBAL NOTE ³

The original principal amount of this Global Note is $400,000,000. The following increases or decreases in this Global Note have been made:



Date of Exchange	Amount of decrease in Principal Amount of this Global Note	Amount of increase in Principal Amount of this Global Note	Principal Amount of this Global Note following such decrease (or increase)	Signature of authorized signatory of Trustee or Note Custodian

³ To be included only if the Note is issued in global form.

A-1-9

EXHIBIT A-2

(Form of Face of Note)



CUSIP 958254 AL8				No. __
ISIN US958254AL80				$__________

WESTERN GAS PARTNERS, LP

5.500% Senior Notes due 2048

Interest Payment Dates: February 15 and August 15

Record Dates: February 1 and August 1

⁴ To be included only if the Note is issued in global form.



WESTERN GAS PARTNERS, LP

By:	Western Gas Holdings, LLC, its general partner

By:
	Name:	Jaime R. Casas
	Title:	Senior Vice President, Chief Financial Officer and Treasurer

TRUSTEE’S CERTIFICATE OF

AUTHENTICATION

This is one of the Debt Securities of the series designated therein referred to in the within-mentioned Indenture.



WELLS FARGO BANK, NATIONAL ASSOCIATION,
As Trustee

By:
	Name:	Patrick Giordano
	Title:	Vice President

Dated: _________

[Signature Page to Global Note]

(Form of Back of Note)

5.500% Senior Notes due 2048

Capitalized terms used herein shall have the meanings assigned to them in the Indenture referred to below unless otherwise indicated.

1. Interest . Western Gas Partners, LP, a Delaware limited partnership (the “Partnership”), promises to pay interest on the principal amount of this Note at 5.500% per annum from August 9, 2018 until maturity. The Partnership shall pay interest semi-annually on February 15 and August 15 of each such year, or if any such day is not a Business Day, on the next succeeding Business Day (each an “Interest Payment Date”). Interest on the Notes shall accrue from the most recent date to which interest has been paid or, if no interest has been paid, from the date of issuance. The first Interest Payment Date shall be February 15, 2019.

⁵ To be included only if the Note is issued in global form.

A-2-2

4. Indenture . The Partnership issued the 5.500% Senior Notes due 2048 (the “Notes”) under an Indenture, dated as of May 18, 2011, by and among the Partnership, the former guarantors party thereto and the Trustee (the “Base Indenture”), as supplemented by the Tenth Supplemental Indenture, dated as of August 9, 2018, between the Partnership and the Trustee (the “Supplemental Indenture” and, together with the Base Indenture, the “Indenture”). The terms of the Notes include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended (15 U.S. Code §§ 77aaa-77bbbb). The Notes are subject to all such terms, and Holders are referred to the Indenture and such Act for a statement of such terms. To the extent any provision of this Note conflicts with the express provisions of the Indenture, the provisions of the Indenture shall govern and be controlling. The Notes are obligations of the Partnership initially in aggregate principal amount of $350,000,000. The Partnership may issue an unlimited aggregate principal amount of Additional Notes under the Indenture. Any such Additional Notes that are actually issued shall be treated as issued and outstanding Notes (and as the same series (with identical terms other than with respect to the issue date, the date of first payment of interest, if applicable, and the payment of interest accruing prior to the issue date) as the initial Notes) for all purposes of the Indenture, including waivers, amendments, redemptions and offers to purchase.

5. Optional Redemption . The Partnership may redeem the Notes, in whole or in part, at any time before February 15, 2048 (the “Par Call Date”), at a redemption price equal to the greater of (1) 100% of the principal amount of the Notes to be redeemed and (2) the sum of the present values of the remaining scheduled payments of principal and interest on such Notes that would have been due if the Notes matured on the Par Call Date (exclusive of interest accrued to the redemption date) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus 40 basis points, plus, in either case, accrued interest, if any, on the principal amount being redeemed to such redemption date. On or after the Par Call Date, the Notes will be redeemable and repayable, at the Partnership’s option, at any time in whole, or from time to time in part, at a price equal to 100% of the principal amount of the Notes to be redeemed plus accrued interest on the Notes to be redeemed to the date of redemption.

A-2-3

For purposes of determining any redemption price, the following definitions shall apply:

“Comparable Treasury Issue” means the United States Treasury security selected by the Quotation Agent as having a maturity comparable to the remaining term of the Notes to be redeemed, calculated as if the maturity date of the Notes were the Par Call Date (the “Remaining Life”) that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the Remaining Life of such Notes; provided , however , that if no maturity is within three months before or after the Par Call Date, yields for the two published maturities most closely corresponding to such United States Treasury security shall be determined and the Treasury Rate will be interpolated or extrapolated from those yields on a straight line basis rounding to the nearest month.

“Primary Treasury Dealer” means a U.S. government securities dealer in The City of New York.

“Quotation Agent” means the Reference Treasury Dealer appointed by the Partnership.

A-2-4

8. Persons Deemed Owners . The registered Holder of a Note shall be treated as its owner for all purposes.

A-2-5

13. Authentication . This Note shall not be valid until authenticated by the manual signature of the Trustee or an authenticating agent.

A-2-6

The Partnership shall furnish to any Holder upon written request and without charge a copy of the Indenture. Requests may be made to:

Western Gas Partners, LP

1201 Lake Robbins Drive

The Woodlands, Texas 77380-1046

Telephone: (832) 636-6000

A-2-7

Assignment Form

To assign this Note, fill in the form below: (I) or (we) assign and transfer this Note to




(Insert assignee’s soc. sec. or tax I.D. no.)




(Print or type assignee’s name, address and zip code)

and irrevocably appoint
agent to transfer this Note on the books of the Partnership. The agent may substitute another to act for him.


Date:

	Your Signature:
		(Sign exactly as your name appears on the face of this Note)

Signature Guarantee:
	(Signature must be guaranteed by a financial institution that is a member of the Securities Transfer Agent Medallion Program (“STAMP”), the Stock Exchange Medallion Program (“SEMP”), the New York Stock Exchange, Inc. Medallion Signature Program (“MSP”) or such other signature guarantee program as may be determined by the Registrar in addition to, or in substitution for, STAMP, SEMP or MSP, all in accordance with the Securities Exchange Act of 1934, as amended.)

A-2-8

SCHEDULE OF INCREASES OR DECREASES IN THE GLOBAL NOTE ⁶

The original principal amount of this Global Note is $350,000,000. The following increases or decreases in this Global Note have been made:



Date of Exchange	Amount of decrease in Principal Amount of this Global Note	Amount of increase in Principal Amount of this Global Note	Principal Amount of this Global Note following such decrease (or increase)	Signature of authorized signatory of Trustee or Note Custodian

⁶ To be included only if the Note is issued in global form.

A-2-9

EXHIBIT B

NOTATION OF GUARANTEE

Each of the Subsidiary Guarantors (which term includes any successor Person under the Indenture), has fully, unconditionally and absolutely guaranteed, to the extent set forth in the Indenture and subject to the provisions in the Indenture, the due and punctual payment of the principal of, and premium, if any, and interest on the [2028][2048] Notes and all other amounts due and payable under the Indenture and the [2028][2048] Notes by the Partnership.

The obligations of each of the Subsidiary Guarantors to the Holders of Debt Securities and to the Trustee pursuant to its Guarantee and the Indenture are expressly set forth in Article XIV of the Base Indenture, as supplemented by Article VIII of the Supplemental Indenture and reference is hereby made to the Indenture for the precise terms of the Guarantee.



	[Subsidiary Guarantors]

	By:
	Name: Title:

B-1

Exhibit 5.1

August 9, 2018

Western Gas Partners, LP

1201 Lake Robbins Drive

The Woodlands, Texas 77380

Ladies and Gentlemen:

We have acted as counsel for Western Gas Partners, LP, a Delaware limited partnership (the “ Partnership ”), with respect to certain legal matters in connection with the registration by the Partnership under the Securities Act of 1933, as amended (the “ Securities Act ”), of the proposed offer and sale by the Partnership of $400,000,000 aggregate principal amount of its 4.750% Senior Notes due 2028 (the “ 2028 Notes ”) and $350,000,000 aggregate principal amount its 5.500% Senior Notes due 2048 (the “ 2048 Notes ” and, together with the 2028 Notes, the “ Notes ”), to be issued and sold pursuant to an underwriting agreement dated August 7, 2018 (the “ Underwriting Agreement ”), by and among the Partnership, Western Gas Holdings, LLC, a Delaware limited liability company (the “ General Partner ”), and the Representatives of the Underwriters named therein. Capitalized terms used but not defined herein shall have the meanings given such terms in the Underwriting Agreement.

The Notes are being offered and sold pursuant to a prospectus supplement, dated August 7, 2018 (the “ Prospectus Supplement ”), filed with the Securities and Exchange Commission (the “ Commission ”) pursuant to Rule 424(b) under the Securities Act on August 8, 2018, to a prospectus dated November 4, 2016 (such prospectus, as amended and supplemented by the Prospectus Supplement, the “ Prospectus ”), included in a Registration Statement on Form S-3 (Registration No. 333-214446) (the “ Registration Statement ”), which Registration Statement became effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act.

The Notes are to be issued pursuant to an Indenture (the “ Base Indenture ”), dated May 18, 2011, by and among the Partnership, the prior subsidiary guarantors party thereto and Wells Fargo Bank, National Association, as trustee (the “ Trustee ”), as supplemented by the Tenth Supplemental Indenture (the “ Supplemental Indenture ”) by and between the Partnership and the Trustee, dated August 9, 2018 (the Base Indenture, as so supplemented, the “ Indenture ”).



Vinson & Elkins LLP Attorneys at Law Austin Beijing Dallas Dubai Hong Kong Houston London Moscow New York Palo Alto Richmond Riyadh San Francisco Taipei Tokyo Washington	1001 Fannin Street, Suite 2500 Houston, TX 77002-6760 Tel +1.713.758.2222 Fax +1.713.758.2346 velaw.com

Western Gas Partners, LP

August 9, 2018 Page 2

We have examined, among other things, originals or copies, certified or otherwise identified to our satisfaction, of (i) the organizational certificates, certificate of limited partnership or formation (as the case may be) and the agreement of limited partnership or limited liability company agreement (as the case may be) of the Partnership and the General Partner, (ii) certain resolutions adopted by the Board of Directors of the General Partner relating to the registration of the Notes and related matters, (iii) certain resolutions adopted by the Pricing Committee of the Board of Directors of the General Partner, (iv) the Registration Statement, (v) the Prospectus, (vi) the Base Indenture and the Supplemental Indenture and (vii) such other certificates, instruments and documents as we consider appropriate for purposes of the opinions hereafter expressed. In addition, we reviewed such questions of law as we considered appropriate.

Based on the foregoing, and subject to the assumptions, limitations and qualifications set forth herein, we are of the opinion that, assuming the Notes have been duly authenticated by the Trustee as contemplated by the Indenture and paid for by the Underwriters as contemplated by the Underwriting Agreement, the Notes will constitute valid and legally binding obligations of the Partnership, enforceable against the Partnership in accordance with their terms.

The opinions expressed herein are qualified in the following respects:

A. As to any facts material to the opinions contained herein, we have made no independent investigation of such facts and have relied, to the extent that we deem such reliance proper, upon certificates of public officials and officers or other representatives of the Partnership and the General Partner.

B. We have assumed that (i) all information contained in all documents submitted to us for review is accurate and complete, (ii) all signatures on all documents examined by us are genuine, (iii) all documents submitted to us as originals are originals and all documents submitted to us as copies conform to the originals of those documents, (iv) each certificate from governmental officials reviewed by us is accurate, complete and authentic and all public records are accurate and complete, (v) each natural person signing any document has the legal capacity to do so; (vi) each person signing any document reviewed by us in a representative capacity had the legal capacity to do so, and (vii) the Notes will be issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Prospectus and the Underwriting Agreement.

C. The opinions expressed herein are limited in all respects to the Delaware Revised Uniform Limited Partnership Act, the Delaware Limited Liability Company Act, the laws of

Western Gas Partners, LP

August 9, 2018 Page 3

the State of New York and the federal laws of the United States of America, and we are expressing no opinion as to the effect of the laws of any other jurisdiction.

D. The opinion is qualified to the extent that the enforceability of any document, instrument or security may be limited by or subject to bankruptcy, insolvency, fraudulent transfer or conveyance, reorganization, moratorium or other similar laws relating to or affecting creditors’ rights generally, and general equitable or public policy principles.

E. We express no opinions concerning (i) the validity or enforceability of any provisions contained in the Indenture that purport to waive or not give effect to rights to notices, defenses, subrogation or other rights or benefits that cannot be effectively waived under applicable law or (ii) the enforceability of indemnification provisions to the extent they purport to relate to liabilities resulting from or based upon negligence or any violation of federal or state securities or blue sky laws.

We hereby consent to the filing of this opinion of counsel as Exhibit 5.1 to the Current Report on Form 8-K of the Partnership dated on or about the date hereof, to the incorporation by reference of this opinion of counsel into the Registration Statement and to the reference to our Firm under the headings “Legal Matters” in the Prospectus. In giving such consent, we do not admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act.



	Very truly yours,

	/s/ Vinson & Elkins L.L.P.