Mont. Code Ann. § 13-1-106

13-1-106 . Time of opening and closing of polls for all elections -- exceptions. (1) Except as provided in subsections (2)(a) and (3), polling places must be open from 7 a.m. to 8 p.m.

(2) (a) A polling place having fewer than 400 registered electors who intend to vote at the polling place must be open from at least noon to 8 p.m. or until all registered electors in any precinct have voted, at which time that precinct in the polling place must be closed immediately.

(b) The determination of whether a polling place has fewer than 400 registered electors who intend to vote at the polling place is calculated by subtracting the number of registered electors who have applied to vote using an absentee ballot from the total number of registered electors.

(c) The election administrator responsible for a polling place opening later than 7 a.m. pursuant to this subsection (2) shall provide notice of the change in polling place hours to affected registered electors who have not received an absentee ballot. The notice must be mailed to each affected registered voter no later than 30 days prior to the election. However, if the polling place opens at the same time in each subsequent election, only one notice mailed before the initial election affected by the change in polling place hours is required.

(3) If an election is held on the same day as a school election and is conducted in the same polling place, the polling place must be opened and closed at the times set for the school election, as provided in 20-20-106 .

(4) If a polling place serves a precinct that lies partially or wholly within the boundaries of an Indian reservation, the hours of operation may not be shortened pursuant to subsection (2) until after the county governing body consults with the governing body of the Indian reservation concerning the potential change in hours of operation.