Montana Oversize & Overweight Permit Requirements & Rules (2026)

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

Rear overhang is limited to 4 ft and front overhang to 3 ft before it counts toward length, and any overhang must be flagged.

2Escort & pilot car requirements

When the load reaches…	Montana requires
12.5 ft wide	1 escort (pilot car)
16.5 ft wide	2 escorts
17 ft high	Escort with a height pole / pole car
150 ft long	1 escort · 200 ft → 2 escorts
15 ft high or 16 ft wide	Route survey required

3When you can travel

Weekend travel allowed within dimensional limits.
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
Gross weight	100,000 lbs

Superloads require a route survey and roughly 5 days of lead time for approval.

5Permit timing

Standard single-trip: ~1 business day to issue.
Superload: ~5 days (route survey + review).
Validity: a single-trip permit is good for ~5 days.

Get the full cost of your load

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Note: these requirements are for planning and are verified as of May 2026. Rules change — always confirm with the state permitting authority before dispatch.

?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 at 12.5 ft wide (two at 16.5 ft), a height pole at 17 ft high.

Can you drive an oversize load at night in Montana?

Travel windows are set on the permit in Montana.

What counts as a superload in Montana?

Over 18 ft wide, 17 ft high, 150 ft long, or 100,000 lbs gross. It requires a route survey 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 →.