Montana oversize permit office
Montana Department of Transportation, Motor Carrier Services Division - Permitting. Call 406-444-7262, 8:00 am - 5:00 pm, Monday through Friday (except holidays) Mountain time.
From Montana's own pages, checked 2026-10-24. Fees and rules change: the state's page is the last word.
- How to get one
- Order and self-issue most permits online in MT eTRIPS, or call the permitting line at 406-444-7262.
- Single trip fee
- Trip Oversize $10.00; Overweight Permit - $3.50 for every 5,000 lbs. of EXCESS axle weight multiplied by the number of 25-mile increments in the proposed route of travelSource
- Legal without a permit
- Width 8 feet 6 inches (102 inches) · Height 14 feet 0 inches · Length 75 feet 0 inches for Truck and Trailer Combinations; 53-foot trailer; single power unit 55 feet · Weight No fixed gross cap published; you must be licensed for the weight and legal on axles and the federal bridge formulaSource
- Superloads
- Loads over 18 feet wide, 150 feet long, 17 feet high, or that need Bridge Bureau approval because of weight, setup or route need a Superload permit.Source
- How fast
- Most single trip permits you issue yourself online in eTRIPS; Class 1 superload decisions come within two working days of a complete application.Source
When you can move
- Daylight
- Off the interstate, loads over 10 ft wide, 150 ft long or 15 ft 6 in high may move in daylight hours only.Source
- At night
- Interstates: any time, day or night, up to 18 ft wide. Other highways: any time up to 10 ft wide, 150 ft long and 15 ft 6 in high.
- Weekends
- Off the interstate, loads over 18 ft wide, 150 ft long or 17 ft high may not move on weekends.
- Holidays
- New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, Christmas Day. Holiday on Fri or Sat: no travel Fri-Sun; on Sun or Mon: no travel Sat-Mon; on Tue-Thu: that day only; Thanksgiving: Thu-Sun. Loads up to 18 ft wide may still use the interstate; off the interstate only loads up to 12 ft 6 in wide (daylight only above 10 ft) and 15 ft 6 in high may move. Next datesSource