Mont. Const. art. VII, § 6

Judicial districts. (1) The legislature shall divide the state into judicial districts and provide for the number of judges in each district. Each district shall be formed of compact territory and be bounded by county lines. (2) The legislature may change the number and boundaries of judicial districts and the number of judges in each district, but no change in boundaries or the number of districts or judges therein shall work a removal of any judge from office during the term for which he was elected or appointed. (3) The chief justice may, upon request of the district judge, assign district judges and other judges for temporary service from one district to another, and from one county to another.