Mont. Code Ann. § 2-1-302

2-1-302 . Resolution of Indian tribes requesting state jurisdiction -- governor's proclamation -- consent of county commissioners. (1) Whenever the governor of this state receives from the tribal council or other governing body of the Confederated Salish and Kootenai Indian tribes or any other community, band, or group of Indians in this state, a resolution expressing its desire that its people and lands be subject to the criminal or civil jurisdiction, or both, of the state to the extent authorized by federal law and regulation, the governor shall issue within 60 days a proclamation to the effect that the specified jurisdiction applies to those Indians and their territory or reservation in accordance with the provisions of this part.

(2) The governor may not issue the proclamation until the resolution has been approved in the manner provided for by the charter, constitution, or other fundamental law of the tribe, if the document provides for approval, and there has been first obtained the consent of the board of county commissioners of each county that encompasses any portion of the reservation of the tribe.