Mont. Code Ann. § 2-1-206

2-1-206 . Cession and retrocession of jurisdiction over Blackfeet highway. (1) Concurrent police jurisdiction shall be and the same is hereby granted to the United States of America over and within all the territory which is now or may hereafter be included in the rights-of-way of the Blackfeet highway, including the highway itself throughout its length between Glacier Park Station and the Canadian boundary line and the rights-of-way of the highways on the Blackfeet Indian reservation connecting the Blackfeet highway with the Glacier park road system, including the highways themselves.

(2) Jurisdiction herein granted shall not vest until the United States of America, through the proper officers, notifies the governor of the state of Montana that it assumes concurrent police jurisdiction over the said rights-of-way and the said highways.

(3) The provisions of the act of congress of March 15, 1958, Public Law 85-343, 85th congress, S.1828, 72 Stat. 35-36, to retrocede to the state of Montana such concurrent police jurisdiction as has been ceded to the United States of America over the rights-of-way of the Blackfeet highway, including the highway itself, and over the rights-of-way of its connection with the Glacier national park road system on the Blackfeet Indian reservation, including the highways themselves, are hereby accepted by the state of Montana as required by section 2 of said act of March 15, 1958 (72 Stat. 35-36), with the understanding on the part of the state of Montana that the laws and regulations of the United States of America pertaining to Glacier national park shall cease to apply to the territory of said rights-of-way and highways as in said act of the congress made and provided.