Mont. Code Ann. § 3-10-234

Whenever a justice of the peace or another person is called in to preside over the court of a justice under 3-10-231, the visiting justice or other person must be paid actual and necessary travel expenses, as defined and provided in 2-18-501 through 2-18-503. If the acting justice is not a justice of the peace receiving a salary, the acting justice must also receive compensation that is proper for the time involved. The cost of implementing this section is a proper charge against the county where the court is held.