Montana Title 7. Local Government § 7-32-301. Residency requirements

A sheriff of a county, mayor of a city, or other person authorized by law to appoint special deputies, marshals, or police officers in this state to preserve the public peace and prevent or quell public disturbance may not appoint as a special deputy, marshal, or police officer any person who has not resided continuously in this state for a period of at least 1 year and in the county where the appointment is made for a period of at least 6 months prior to the date of appointment.