A board of county commissioners shall transfer its control over and responsibility for a county road when the department of transportation notifies it that: (1) a federal or state highway has been established and definitely located over a county road; (2) funds are available for immediate construction of the highway; (3) the highway will be improved and maintained by the department.
Transfer To State Of County Responsibility For Right-Of-Way
Mont. Code Ann. § 7-14-2109, under General Provisions Related to County Roads.
Mont. Code Ann. § 7-14-2109