SECONDSUPPLEMENTAL INDENTURE

Exhibit 4.3

EXECUTION VERSION

SECOND SUPPLEMENTAL INDENTURE

SECOND SUPPLEMENTAL INDENTURE (this “Second Supplemental Indenture”) dated as of October 14, 2014, by and among Atlas Energy Holdings Operating Company, LLC, a Delaware limited liability company (the “Company”), Atlas Resource Finance Corporation, a Delaware corporation (“Finance Co” and, together with the Company, the “Issuers”), Atlas Resource Partners, L.P., a Delaware limited partnership (“ARP”), each of the parties identified under the caption “Subsidiary Guarantors” on the signature pages hereto (the “Subsidiary Guarantors” and, together with ARP, the “Guarantors”) and Wells Fargo Bank, National Association, a national banking association, as Trustee (the “Trustee”).

WITNESSETH:

WHEREAS, the Issuers, the Guarantors, and the Trustee are party to an indenture, dated as of July 30, 2013 (the “Base Indenture”) as supplemented by a supplemental indenture, dated as of July 31, 2013 (the “First Supplemental Indenture” and, together with the Base Indenture and this Second Supplemental Indenture, the “Indenture”), providing for the issuance by the Issuers of their 9.25% Senior Notes due 2021;

WHEREAS, pursuant to the Base Indenture and the First Supplemental Indenture, $250,000,000 aggregate principal amount of the Issuers’ 9.25% Senior Notes due 2021 (the “Existing Notes”) were issued on June 30, 2013;

WHEREAS, Section 2.01 of the Base Indenture provides that the Issuers may, from time to time and in accordance therewith, create and issue Additional Notes (as defined in the Base Indenture) under the Base Indenture;

WHEREAS, the Issuers wish to issue an additional $75,000,000 aggregate principal amount of their 9.25% Senior Notes due 2021 as Additional Notes (the “New Notes”);

WHEREAS, Section 9.01 of the Base Indenture, as supplemented by the First Supplemental Indenture, provides that, without the consent of the Holders of any Notes, the Issuers, the Guarantors and the Trustee may enter into one or more indentures supplemental to the Base Indenture to make any change that does not adversely affect the legal rights of any Holder;

WHEREAS, the Issuers and the Guarantors are authorized to execute and deliver this Second Supplemental Indenture;

WHEREAS, the Issuers have requested that the Trustee execute and deliver this Second Supplemental Indenture; and

WHEREAS, all conditions and requirements necessary to the execution and delivery of this Second Supplemental Indenture have been done and performed, and the execution and delivery hereof has been in all respects authorized.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Issuers, the Guarantors and the Trustee mutually covenant and agree as follows:

1. Defined Terms. Capitalized terms used herein without definition shall have the meanings assigned to them in the Base Indenture. The words “herein,” “hereof” and “hereby” and other words of similar import used in this Second Supplemental Indenture refer to this Second Supplemental Indenture as a whole and not to any particular section hereof.

2. Amount of New Notes. The aggregate principal amount of New Notes to be authenticated and delivered under this Second Supplemental Indenture on October 14, 2014 is $75,000,000.

3. Terms of New Notes. The New Notes are to be issued as Additional Notes under the Indenture and shall:

4. Ratification of Base Indenture; Second Supplemental Indenture Part of Indenture. Except as expressly amended hereby, the Base Indenture, as supplemented by the First Supplemental Indenture, is in all respects ratified and confirmed and all the terms, conditions and provisions thereof shall remain in full force and effect. This Second Supplemental Indenture shall form a part of the Base Indenture, as supplemented by the First Supplemental Indenture, for all purposes, and every Holder of a Note or New Note heretofore or hereafter authenticated and delivered shall be bound hereby.

5. GOVERNING LAW. THIS SECOND SUPPLEMENTAL INDENTURE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW YORK BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

6. Trustee’s Assumption; Trustee Makes No Representation. The Trustee assumes no duties, responsibilities or liabilities under this Second Supplemental Indenture other than as set forth in the Base Indenture, as supplemented by the First Supplemental Indenture. The Trustee makes no representation as to the validity or sufficiency of this Second Supplemental Indenture.

7. Counterparts. The parties may sign any number of copies of this Second Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

8. Effect of Headings. The Section headings herein are for convenience only and shall not affect the construction thereof.

9. FATCA. The Issuers hereby confirm to the Trustee that this Second Supplemental Indenture has not resulted in a material modification of the Notes for Foreign Accounting Tax Compliance Act (“FATCA”) purposes. The Issuers shall give the Trustee prompt written notice of any material modification of the Notes deemed to occur for FATCA purposes. The Trustee shall assume that no material modification for FATCA purposes has occurred regarding the Notes, unless the Trustee receives written notice of such modification from the Issuers.

IN WITNESS WHEREOF, the parties hereto have caused this Second Supplemental Indenture to be duly executed, all as of the date first written above.