Exhibit 4.1

SUPPLEMENTAL INDENTURE

SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of August 13, 2013, among Pinnacle Entertainment, Inc., a Delaware corporation (the “Company”), the entities listed on Appendix A hereto (the “Guarantors”), each a subsidiary of the Company, and The Bank of New York Mellon Trust Company, N.A., as trustee under the Indenture referred to below (the “Trustee”).

W I T N E S S E T H

WHEREAS, PNK Finance Corp., a former wholly-owned subsidiary of the Company formed as a Delaware corporation (“Escrow Issuer”), has heretofore executed and delivered to the Trustee an indenture (the “Indenture”), dated as of August 5, 2013, providing for the issuance of 6.375% Senior Notes due 2021 (the “Notes”);

WHEREAS, the Notes were issued and sold in connection with the Acquisition;

WHEREAS, on the date hereof, the Company consummated the Acquisition and, following the consummation of the Acquisition, Escrow Issuer merged with and into the Company, with the Company as the surviving Person;

WHEREAS, pursuant to this Supplemental Indenture, the Company will expressly assume the due and punctual payment of the principal of, and premium, if any, and interest and Additional Interest, if any, on all of the Notes and the performance of every covenant of the Notes and the Indenture and the Registration Rights Agreement on the part of Escrow Issuer to be performed or observed, and the Guarantors shall unconditionally guarantee all of the Company’s Obligations under the Notes and the Indenture, all on the terms set forth herein (the “Guaranty”); and

WHEREAS, pursuant to Section 9.01 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Company, the Guarantors and the Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

1. CAPITALIZED TERMS. Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2. ASSUMPTION OF OBLIGATIONS. The Company hereby assumes the due and punctual payment of the principal of, and premium, if any, and interest and Additional Interest, if any, on all of the Notes and the performance of every covenant of the Notes and the Indenture and the Registration Rights Agreement on the part of Escrow Issuer to be performed and observed and hereby joins and becomes a party to and is hereby bound by all other applicable provisions of the Indenture and the Notes.

3. GUARANTY. Each of the Guarantors hereby agrees to provide an unconditional Guaranty on the terms and subject to the conditions set forth in the Guaranty and in the Indenture including but not limited to Article 10 thereof.

4. NO RECOURSE AGAINST OTHERS. No past, present or future director, officer, employee, incorporator, stockholder or agent of the Guarantors, as such, shall have any liability for any obligations of the Company or any Guarantor under the Notes, any Guaranties, the Indenture or this Supplemental Indenture or for any claim based on, in respect of, or by reason of, such obligations or their creation. Each Holder of the Notes

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by accepting a Note waives and releases all such liability. The waiver and release are part of the consideration for issuance of the Notes. Such waiver may not be effective to waive liabilities under the federal securities laws and it is the view of the SEC that such a waiver is against public policy.

5. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE 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. COUNTERPARTS. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

7. EFFECT OF HEADINGS. The Section headings herein are for convenience only and shall not affect the construction hereof.

8. 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 recitals are made solely by the Company and the Guarantors.

[Signature page follows.]

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

APPENDIX A

List of Guarantors