Wyo. Stat. § 24-3-127
The board of county commissioners of any county of this state may, in its discretion, enter into cooperative agreements with the forest service of the U.S. department of agriculture or other federal agency to provide for the joint construction, maintenance and use of roads located within the boundaries of the county, where such roads are used by the forest service or other federal agency in the protection, administration and utilization of the national forests and national recreation areas or other federal lands and are also used by communities or persons within or adjacent to such national forests or other federal lands in the use and development of the resources thereof or where such roads otherwise serve the needs of the public.
W.S. 24-3-127