Mont. Code Ann. § 81-4-311

Upon creation of a herd district pursuant to 81-4-301, 81-4-304, or 81-4-322, fences must be constructed by the entities creating the herd district. Upon approving an annexation to an existing herd district pursuant to 81-4-310, fences must be constructed by the entities being annexed into the herd district. All fences must be maintained pursuant to 70-16-205. All fences must conform with the requirements of 81-4-101. An action to enforce the provisions of this section may be brought by the aggrieved party in the district court in the county where the land is situated.