Mont. Code Ann. § 72-5-311
Venue for proceedings for court appointment of guardian
72-5-311 . Venue for proceedings for court appointment of guardian. The venue for guardianship proceedings for an incapacitated person is in the place where the incapacitated person resides or is present. If the incapacitated person is admitted to an institution pursuant to order of a court of competent jurisdiction, venue is also in the county in which that court sits.