Exhibit 4.10

SIXTH SUPPLEMENTAL INDENTURE

SIXTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”) dated as of August 13, 2013 among the entities listed on Appendix A hereto (the “Guarantying Subsidiaries”), each a subsidiary of Pinnacle Entertainment, Inc. (the “Company.”), the Company, the other Guarantors (as defined in the Indenture referred to herein) 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, the Company has heretofore executed and delivered to the Trustee an indenture (the “Original Indenture”), dated as of May 6, 2010 and as further amended by the First Supplemental Indenture, dated as of January 26, 2011, the Second Supplemental Indenture, dated as of January 28, 2011, the Third Supplemental Indenture, dated as of January 28, 2011, the Fourth Supplemental Indenture, dated as of August 1, 2012, and the Fifth Supplemental Indenture, dated as of January 29, 2013, as so supplemented (together with the Original Indenture, the “Indenture”) providing for the issuance of 8.75% Senior Subordinated Notes due 2020 (the “Notes”);

WHEREAS, on the date hereof, the Company consummated its acquisition (the “Acquisition”) of Ameristar Casinos, Inc. (“Ameristar”) by merging a wholly owned subsidiary of the Company with and into Ameristar, and immediately thereafter merging Ameristar with and into the Company, with the Company continuing as the surviving entity, pursuant to that certain Agreement and Plan of Merger, dated as of December 20, 2012, as amended by the First Amendment, entered into on February 1, 2013, and the Second Amendment, entered into on March 31, 2013, among the Company, Ameristar, PNK Holdings, Inc. and PNK Development 32, Inc.;

WHEREAS, each of the Guarantying Subsidiaries was a former direct or indirect wholly-owned subsidiary of Ameristar and became a direct or indirect wholly-owned subsidiary of the Company upon consummation of the Acquisition;

WHEREAS, the Indenture provides that in connection with the Acquisition, the Guarantying Subsidiaries shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guarantying Subsidiaries shall unconditionally guarantee all of the Company’s Obligations under the Notes and the Indenture on the terms and conditions set forth herein (the “Guaranty”);

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

WHEREAS, all acts and requirements necessary to make this Supplemental Indenture the legal, valid and binding obligation of the Guarantying Subsidiaries and the Company have been done.

NOW THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the parties 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.

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2. AGREEMENT TO GUARANTY. Each of the Guarantying Subsidiaries 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 11 thereof.

3. NO RECOURSE AGAINST OTHERS. No past, present or future director, officer, employee, incorporator, stockholder or agent of the Guarantying Subsidiaries, as such, shall have any liability for any obligations of the Company or any Guarantying Subsidiary 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 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.

4. 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.

5. COUNTERPARTS. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of such executed copies together shall represent the same agreement.

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

7. 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 Guarantying Subsidiaries.

8. SUCCESSORS. All agreements of the Company and each of the Guarantying Subsidiaries in this Supplemental Indenture shall bind its successors, except as otherwise provided in this Supplemental Indenture. All agreements of the Trustee in this Supplemental Indenture shall bind its successors.

[Signature page follows.]

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

APPENDIX A

List of Guarantying Subsidiaries