Does a Montana truck need a USDOT number for in-state work?

Yes. Montana requires a USDOT number for in-state commercial vehicles at 26,001 lb and over (GVWR, GCWR or actual weight, whichever is greater), even if they never cross a state line.

Checked against Montana’s official sources in September 2026.

The rule in Montana

Who it covers: Intrastate carriers, for-hire and private, operating commercial motor vehicles as defined for intrastate purposes (26,001 lb or more, passenger vehicles, placarded hazmat).

The weight line: For intrastate safety purposes, a Montana commercial motor vehicle is one at 26,001 lb or more (the greater of the rating or actual weight), or a passenger or placarded-hazmat vehicle. Farm vehicles operating solely in Montana are excluded from the statutory 26,001 lb category.

Exemptions the state lists:

Farm vehicles operating solely in Montana (excluded from the 26,001 lb intrastate category in MCA 61-10-154(2)(c))

“For the purpose of 49 CFR 390.21, the department will assign a United States Department of Transportation (USDOT) number to each intrastate motor carrier and that number, in addition to the name or trade name of the motor carrier, must be marked on each self-propelled commercial motor vehicle” source

“any motor vehicle or vehicle combination used in intrastate commerce that has a gross vehicle weight rating, gross combination weight rating, gross vehicle weight, or gross combination weight, whichever is greater, of 26,001 pounds or more and that is not a farm vehicle operating solely in Montana;” source

The rule: ARM 18.8.1502(2)(c)-(d) (intrastate MCS-150 and USDOT marking), ARM 18.8.1501(2) (intrastate CMV definition), MCA 61-10-154

Who to ask: Montana Department of Transportation (MDT), Motor Carrier Services Division

Safety rules for in-state trucks

MDT adopts by reference 49 CFR parts 373, 375, 377-379, 382, 383, 385, 386 subpart F, 387 and 390-399 (as updated through April 25, 2024) for carriers it regulates under MCA 61-10-154, with state modifications. (ARM 18.8.1502(1))

Intrastate carriers must file the MCS-150 before starting operations and every 24 months.
Intrastate vehicles must show the USDOT number followed by 'MT'.
For intrastate safety purposes, the federal CMV definition is raised from 10,001 to 26,001 lb.
MDT states that intrastate carriers with a USDOT number must do the biennial MCS-150 update because Montana adopted the federal rules.

The federal lines, which apply in Montana too

10,001 lb and interstate commerce: a USDOT number, a medical card, a driver qualification file, the hours-of-service rules and daily inspections (49 CFR 390.5).
26,001 lb: a CDL, for a single vehicle or a combination towing more than 10,000 lb (383.5). The CDL rules cover in-state driving as well (383.3), and drug and alcohol testing follows the CDL (382.103).

Check your own truck and trailer

Questions

Does Montana require a USDOT number for intrastate trucks?

Yes. Montana requires a USDOT number for in-state commercial vehicles at 26,001 lb and over (GVWR, GCWR or actual weight, whichever is greater), even if they never cross a state line.

What is the CDL weight in Montana?

The same as everywhere: 26,001 lb for a single vehicle, or a combination of 26,001 lb towing more than 10,000 lb. The federal CDL rules apply to in-state driving too (49 CFR 383.3), and drug and alcohol testing follows the CDL (382.103).

Who administers the rule in Montana?

Montana Department of Transportation (MDT), Motor Carrier Services Division.

What we could not confirm

Montana's statute also lists 'any for-hire motor carrier or any private motor carrier' without a weight, so whether a carrier with only trucks under 26,001 lb needs a USDOT number was not confirmed.
Montana's in-state age and physical rules for drivers (ARM 23.3.505 and 23.3.506) were not read.

Sources

General information, not legal advice. It summarises Montana’s published rules as read in September 2026; confirm with MDT Motor Carrier Services or FMCSA.