Mont. Code Ann. § 20-6-308
Organization of joint high school district
20-6-308 . Organization of joint high school district. The boundaries of a high school district that encompass a county's portion of a joint elementary district where an elementary school is operated may be changed to establish a joint high school district. The high school district boundary change must be a transfer of all the territory located in another county's portion of the same joint elementary district and must be made pursuant to the procedures provided in 20-6-105 .