Montana Oversize & Overweight Permits for Heavy Haul
Montana permit rules, legal limits and escort triggers, and how we book heavy haul carriers for moves in and through the state.
Quick answer
Do I need a permit to move an oversize load in Montana?
Yes, once the load is wider than 8 ft 6 in, taller than 14 ft or over the axle and bridge-formula limits; Montana has no fixed 80,000 lb cap for loads that meet them. MDT issues permits through eTRIPS: a single trip oversize permit is $10, and overweight loads pay by distance and by how far the axles are over legal.
Updated November 2026 by the Quickway Transports broker team (FMCSA MC# 1245224).
Heavy haul and oversize freight in Montana
Montana's heavy freight covers long distances: I-90 crosses the state from Idaho through Missoula, Butte, Bozeman and Billings toward Wyoming, I-15 runs from Idaho through Butte, Helena and Great Falls to the Canadian border, and I-94 heads east from Billings into North Dakota. Mining and energy equipment, farm machinery and freight between the Pacific Northwest and the Midwest make up much of it. We book carriers for moves within Montana or across it.
Montana is generous on the Interstate: loads up to 18 ft wide can travel there around the clock, holidays included, and many routine permits self-issue in eTRIPS. The limits sit on the two-lane highways, where loads over 10 ft wide move in daylight and the widest stop for holiday weekends, and in spring, when MDT posts load restrictions on roads that start breaking up.
What are the legal size and weight limits in Montana?
Under the oversize load regulations in Montana, a load above any of these limits needs a state oversize or overweight permit.
| Width | 8 ft 6 in |
|---|---|
| Height | 14 ft |
| Semitrailer length | 53 ft |
| Gross weight | 131,060 lbs |
| Single axle | 20,000 lbs |
| Tandem axle | 34,000 lbs |
Limits are set by MCA 61-10-102 to 61-10-107. Montana sets no fixed 80,000 lb gross cap: a load legal on its axles and the bridge formula, on a truck licensed for the weight, needs no permit, and reducible loads top out at 131,060 lbs.
Who issues Montana oversize permits?
MDT's Motor Carrier Services Division in Helena issues permits through eTRIPS, which self-issues trip, term and weight permits around the clock when no special approval is needed, and after hours the Billings and Haugan weigh stations can help. A single trip permit is good for the dates printed on it and becomes void when the load leaves Montana.
Anything past 18 ft wide, 17 ft high or 150 ft long counts as a Montana superload; below that, a single trip permit covers the move. A county or city permit may be needed for local roads in addition to the MDT permit.
Permit system: MT eTRIPS (Electronic Transportation Routing and Intra/Interstate Permitting System)
What do Montana oversize and overweight permits cost?
- request_quote Oversize single trip: $10. Annual oversize term permit, up to 15 ft wide and 95 ft long: $75.
- request_quote Legal axle weights but over the bridge formula: $10 for trips up to 100 miles, $30 for 100 to 199 miles and $50 for longer ones.
- request_quote Over the axle limits: $3.50 for each 5,000 lbs of total excess axle weight per 25 miles, with miles and weight rounded up.
- request_quote Winter weight permit, up to 10% over legal from December 1 to March 7 off the Interstate: $50 for 30 days or $150 for the season.
- request_quote eTRIPS passes card and online payment fees to the carrier.
Worked example: 31,250 lbs of excess axle weight over 389 miles
MDT's own example: 31,250 lbs of excess axle weight rounds up to 35,000 lbs, seven 5,000 lb steps at $3.50, or $24.50 per 25 miles. A 389-mile trip rounds up to 16 segments of 25 miles, so the permit costs $24.50 x 16 = $392.
Montana pilot car and escort requirements
- local_police Non-Interstate: one front pilot over 12 ft 6 in wide, front and rear over 16 ft 6 in, and at least two front and one rear over 18 ft.
- local_police Interstate: no pilot up to 16 ft 6 in wide, one rear pilot over 16 ft 6 in, and two side by side at the rear over 18 ft.
- local_police Length on non-Interstate highways: one rear pilot over 150 ft, front and rear over 200 ft.
- local_police Over 17 ft high: a front pilot with a height pole, and a rear pilot as well over 24 ft.
- local_police Overweight loads crossing bridges at 10 mph need at least one rear pilot, and bridge-centerline crossings need two.
- local_police Montana sets no pilot driver certification; pilot vehicles carry signs, amber lights and two-way radios and stay within 1,000 ft of the load.
What hours can oversize loads move in Montana?
- calendar_today Interstate: travel at any hour, holidays included, for loads up to 18 ft wide.
- calendar_today Non-Interstate: any hour up to 10 ft wide, 150 ft long and 15 ft 6 in high, and daylight only above that.
- calendar_today Off the Interstate, no weekend moves for loads past 18 ft wide, 17 ft high or 150 ft long.
- calendar_today Holidays: Christmas, New Year's Day, Thanksgiving (Thursday to Sunday), Memorial Day, Labor Day and the Fourth of July, stretched to the weekend when they fall beside one, stop larger non-Interstate loads and Interstate loads over 18 ft.
- calendar_today Two local limits: loads wider than 9 ft may use MT-35 from Polson to Bigfork only when the trip begins or ends on that stretch, and US-12 in Deep Creek Canyon takes nothing wider than 12 ft.
Seasonal weight limits in Montana
In spring MDT posts load and speed restrictions on highways that start breaking up, such as 8 tons per single axle, and no overweight permit is valid on a restricted highway without the district administrator's approval. There are no fixed dates; postings stay until MDT lifts them. Winter runs the other way: a winter weight permit allows 10% over legal on non-Interstate roads from December 1 to March 7.
Montana Oversize Load Questions
Permits, escorts and travel rules for oversize moves in Montana.
How much is a Montana oversize permit?
Can oversize loads travel at night in Montana?
Does Montana have a gross weight limit?
When are Montana's oversize holiday restrictions?
What is a superload in Montana?
Sources
We last checked the figures above against these official sources in October 2026. Before each move, the carrier's permit service confirms the rules in force that day.
- MDT Permits for Commercial Motor Carriers
- MDT MT Permitting Reference and FAQs (updated 01/27/2026)
- MDT Montana Permit Restrictions - eTRIPS (updated 07/27/2026)
- MDT Montana Holiday Permit Restrictions for 2026
- MDT Superload Application Instructions (rev. 04/08/2026)
- MDT 2026 Commercial Vehicle Size and Weight and Safety Trucker's Handbook (9th ed., April 2026)
- MDT Load and Speed Restrictions (checked 2026-10-17)
- MCA Title 61, Chapter 10, Part 1 (2025 MCA)
- MCA 61-10-124 Special permits, fees
- MCA 61-10-125 Other fees
- ARM 18.8.509 Special permit restrictions, super-load (eff. 10/21/2023)
- ARM 18.8.511A When pilot vehicles are required (eff. 3/21/2026)
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Heavy Haul Solutions for Oversized and Specialized Loads
Near Montana: states and services
- Heavy Haul in Wyoming →Oversize moves in and through Wyoming: Cheyenne, Casper, Gillette and the WY permit rules.
- Heavy Haul in North Dakota →Oversize moves in and through North Dakota: Fargo, Bismarck, Grand Forks and the ND permit rules.
- Heavy Haul in South Dakota →Oversize moves in and through South Dakota: Sioux Falls, Rapid City, Aberdeen and the SD permit rules.
- Heavy Haul in Idaho →Oversize moves in and through Idaho: Boise, Meridian, Nampa and the ID permit rules.
- Heavy Equipment Transport →Which trailer, permits and preparation each kind of construction, farm, mining and industrial machine needs.
- Heavy Haul Trucking →Oversize and overweight loads on RGN, step-deck and flatbed trailers, with permits, pilot cars and route surveys arranged.