In Montana, any load that exceeds the legal size or weight limits requires an oversize/overweight permit before it moves. Below are the legal limits and the requirements that apply at each threshold.
1When you need a permit
A load is oversize or overweight once it passes any of these:
| Dimension | Montana legal limit | Permit if over |
|---|---|---|
| Width | 8 ft 6 in | Wider |
| Height | 14 ft | Taller |
| Length (combination) | 75 ft | Longer |
| Gross weight | 80,000 lbs | Heavier |
| Single axle | 20,000 lbs | Heavier |
| Tandem axle | 34,000 lbs | Heavier |
Montana sets no general front-overhang allowance — freight ahead of the trailer counts toward its length limits.
2Escort & pilot car requirements
| Once the load is over… | Montana requires |
|---|---|
| 12 ft 6 in wide | 1 escort (pilot car) |
| 16 ft 6 in wide | 2 escorts |
| 17 ft high | Escort with a height pole / pole car |
| 150 ft long | 1 escort · 200 ft → 2 escorts |
| 17 ft high or 20 ft wide | Route survey required |
3When you can travel
- Daylight only — 30 min before sunrise to 30 min after sunset.
- Weekends: Weekend travel is restricted for loads over 18 ft wide or 17 ft high or 150 ft long.
- Non-Interstate highways: night travel up to 10 ft wide, 15 ft 6 in high and 150 ft long. Interstates: 24/7 up to 18 ft wide..
- Holiday blackouts: New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, Christmas Day.
4Superloads in Montana
A load is a superload once it exceeds any of these:
| Superload trigger | Threshold |
|---|---|
| Width | 18 ft |
| Height | 17 ft |
| Length | 150 ft |
Superloads require individual review and roughly 5 days of lead time for approval.
5Permit timing
- Superload review: ~5 days.
Get the full cost of your load
FreightDeck estimates every cost on an oversize move — permits, escorts, police, route survey, engineering, and the truck rate — for your exact load and route, across all 48 states and Canada, up to superload size.
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?Montana permit FAQ
When do I need an oversize permit in Montana?
Once a load exceeds any legal limit: 8 ft 6 in wide, 14 ft high, 75 ft long (combination), or 80,000 lbs gross.
When do I need a pilot car in Montana?
Montana requires one escort over 12 ft 6 in wide (two over 16 ft 6 in), and a height pole over 17 ft high.
Can you drive an oversize load at night in Montana?
Daylight only, 30 min before sunrise to 30 min after sunset. Non-Interstate highways: night travel up to 10 ft wide, 15 ft 6 in high and 150 ft long. Interstates: 24/7 up to 18 ft wide. Weekend travel is allowed within limits.
What counts as a superload in Montana?
Over 18 ft wide, 17 ft high, or 150 ft long. It requires individual review and about 5 days of lead time.
How much does a Montana oversize permit cost?
The state permit fee depends on the load's size and weight. The full cost of a move also includes escorts, police, route surveys, engineering, and the truck rate, which vary by route. FreightDeck estimates all of it for your exact load — price your Montana load with FreightDeck →.
How long does it take to get an oversize permit in Montana?
Montana does not publish a standard processing time for routine permits; superload review takes about 5 days.
Can oversize loads move on weekends and holidays in Montana?
Weekend travel is restricted for loads over 18 ft wide or 17 ft high or 150 ft long. Movement stops on New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day (Full days incl. holiday weekend: Fri/Sat holiday -> Fri-Sun; Sun/Mon -> Sat-Mon; Tue-Thu -> that day; Thanksgiving -> Thu-Sun. Interstate: >18 ft W barred; non-Interstate: >12'6" W/150 ft L/15'6" H barred, 10-12'6" W daylight only); check the permit conditions for exact times.
How much overhang is allowed in Montana?
Montana sets no general front-overhang allowance — freight ahead of the trailer counts toward its length limits.
Does Montana require a route survey?
Yes, once a load is over 17 ft high or 20 ft wide. The survey checks every bridge, sign, signal and wire on the route and is filed with the permit; it usually takes longer than the permit itself, so start it first. What a route survey involves →
Are any loads exempt from oversize permits in Montana?
Montana publishes exemptions or relaxed rules for farm equipment, logging trucks, and ioh and hay-hauling vehicles (width) (for example daylight only; 100 miles or less; incidental to owner's farming operations; rear lights per 61-9-219(4). over 12.5 ft wide: lead flag-vehicle escort (not required for dual-wheel tractors under 15 ft or county-road moves within 100 mi). over 16.5 ft on an interstate or 4-lane highway: trailing flag-vehicle escort. hazardous areas: front and rear escorts). Exemptions are narrow and usually limited to specific roads and daylight hours; anything else over the legal limits needs a permit.
Does a Montana permit cover North Dakota?
No. Every state issues its own permit, and a move crossing into North Dakota, South Dakota, or Wyoming needs a separate permit there with that state's escort and travel rules. FreightDeck prices every state on the route in one quote.