Car speed limits in Montana (2026)
Last reviewed: 9 October 2026
In short: The speed limit is 25 mph in an urban district. On other public highways it is 70 mph by day and 65 mph at night, and on interstates it is 80 mph outside urbanised areas of 50,000 or more and 65 mph inside them. Local authorities may set school-zone limits of at least 15 mph, where fines are doubled. Work-zone limits are posted, and fines are doubled if a highway worker is present.
| Rule | What applies |
|---|---|
| Built-up areasPassenger car on public roads | 25 mph in an urban district [1] |
| Outside built-up areas (single carriageway)Passenger car on public roads | 70 mph day, 65 mph night [1] |
| Outside built-up areas (dual carriageway or expressway)Passenger car on public roads | 75 mph day, 70 mph night on four-lane national highway sections of 10 miles or more [1] |
| MotorwaysPassenger car on public roads | 80 mph outside urbanised areas of 50,000 or more; 65 mph inside [1] |
| School zonesPassenger car on public roads | No fixed statewide figure: a local authority may lower the limit in a signed school zone to not less than 15 mph, at all times or at the times shown on the signs. The fine for speeding there is at least double the normal fine. [2] |
| Roadworks zonesPassenger car on public roads | The work-zone speed limit is set by the Department of Transportation or the local authority and shown on signs. The fine for a traffic offence is at least doubled if a highway worker was present within 1,000 feet. [3] |
Notes
- Limits may be altered by the transportation commission or a local authority.
- Applies on any other public highway. "Daytime" runs from half an hour before sunrise to half an hour after sunset. Limits may be altered by the transportation commission or a local authority.
- Applies to portions of a national highway of 10 miles or more that have been expanded to four lanes and are not subject to a permanent special speed zone.
- Applies on interstate highways at all times.
Sources
- Montana Legislature: Montana Code Annotated 2025, 61-8-303 Speed restrictions - definitions (consulted 9 October 2026) · all sources
- Montana State Legislature: MCA 61-8-310 (school zones) and 61-8-726 (school-zone penalty doubled), Montana Code Annotated 2025 (consulted 10 October 2026) · all sources
- Montana State Legislature: MCA 61-8-314. Traffic violations in work zone, Montana Code Annotated 2025 (consulted 10 October 2026) · all sources
Montana and neighbouring states
| State | Built-up areas | Outside built-up areas (single carriageway) | Outside built-up areas (dual carriageway or expressway) | Motorways |
|---|---|---|---|---|
| Montana | 25 mph | 70 mph day / 65 night | 75 mph day / 70 night | 80 mph (65 in urban areas) |
| Idaho | 35 mph | 65 mph state hwys; 55 mph other | 65 mph state hwys; 75 mph interstates | 75 mph (interstates) |
| North Dakota | 25 mph | 55 mph; 65 mph if posted | 70 mph | 80 mph |
| South Dakota | 25 mph unposted | 65 mph; 55 mph township roads | Up to 70 mph where set and posted | 80 mph |
| Wyoming | 30 mph | 70 mph state highways; 65 mph other paved | — | 75 mph; 80 mph where designated |
More rules in Montana
- CannabisPossession for personal use: Legal for adults 21+, within limits · Growing at home: Yes: 2 mature plants, 2 seedlings
- Minimum age for a car driving licenceMinimum age for a car licence: 15 (after 6 months on a learner licence) · Earliest age to drive a car supervised: 14.5 with a traffic education course
- E-bikes and speed pedelecsLegal class: Bicycle (one class)
- FireworksConsumers may buy and use category F2 fireworks: Yes (permissible fireworks)
- Knives and pepper sprayFolding pocket knives: Carry offence covers firearms only · Locking or one-handed knives: No section on automatic knives listed
- Statutory minimum wageNational statutory minimum wage: Yes · Current adult minimum wage (gross): $10.85 per hour
- Seat belts and child seatsSeat belt compulsory in front seats: Yes, every designated seat · Seat belt compulsory in rear seats: Yes, every designated seat
- Tobacco and nicotine age limitsMinimum age to buy tobacco: 21 · Minimum age to buy e-cigarettes: 21
- Drinking age and alcohol salesMinimum age to buy beer and wine: 21 (sales/provision banned) · Minimum age to buy spirits: 21 (sales/provision banned)
- Drink-driving limitsBlood alcohol limit for ordinary drivers: 0.08% · Lower limit for novice or young drivers: 0.02% under 21
Related pages
General information, not legal advice. Rules change: check the official source before you fly or ride.