Montana Oversize Permits

Legal size/weight limits, escort thresholds, travel restrictions, and permit office contact for Montana.

⚠ REFERENCE ONLY — NOT A PERMIT. VERIFY WITH THE STATE BEFORE YOU TRAVEL.

These figures are a reference summary of publicly published state rules, not a substitute for a state-issued permit and not legal advice. Rules change — always confirm current limits and requirements directly with the state permit office before you plan or run a move. Last verified: 2026-07-16. Oversize Ops is NOT responsible and CANNOT be held liable for decisions made from this reference. Official source ↗

Legal Maximum Dimensions (no permit required)

Width: 8.5ft (102in)
Height: 14ft (168in)
Max semitrailer length: 53ft
Gross Weight: 80,000 lbs
Single Axle: 20,000 lbs
Tandem Axle: 34,000 lbs

MCA 61-10-103: a vehicle unladen or with load may not exceed 14 ft (168 in). Exception for implements of husbandry and hay/straw moved up to 25 miles at not over 15 ft 6 in, provided the route has no overhead obstacle 17 ft or lower.

Official source for this height limit →

MCA 61-10-104(2)(a): "Truck tractor-semitrailer, truck tractor-semitrailer-trailer, and truck tractor-semitrailer-semitrailer combinations are not subject to a combination length limit." 53 ft semitrailer statewide, all roads, no road-class distinction. ⚠️ TWO DECOYS: (1) the 75 ft in 61-10-104(2)(c) applies to "all other combinations of vehicles", NOT tractor-semitrailers — that is what our previous figure was; (2) MCA 61-10-124 is the SPECIAL-PERMIT section, so its 95/100/105/110 ft figures are permit ceilings and its 57 ft semitrailer requires a term permit. The 28.5 ft / 61 ft figures are doubles, not single semitrailers.

Official source for these length limits →

Escort / Pilot Car Thresholds (see glossary for terms, certification requirements for the driver)

These escort figures are route-dependent — they can change with road classification, lane width, two-lane vs multilane, and time of day. Confirm with the permit office before dispatching.

Front escort required over: 12.5ft wide
Rear escort required over: 16.5ft wide
Both escorts required over: 16.5ft wide
Height escort required over: 17ft tall

Montana pilot-car triggers differ by highway type (ARM 18.8.511A). NON-INTERSTATE: over 12'6" to 16'6" wide = 1 FRONT pilot; over 16'6" to 18' wide = 1 FRONT + 1 REAR; over 18' to 24' wide = 2 FRONT + 1 REAR; over 24' wide = 2 FRONT + 2 REAR; over 150' long = 1 REAR; over 200' long = 1 FRONT + 1 REAR. INTERSTATE: over 16'6" to 18' wide = 1 REAR pilot; over 18' wide = 2 REAR pilots side-by-side. HEIGHT (all roads): over 17' to 24' high = 1 FRONT pilot with height pole; over 24' high = 1 FRONT with height pole + 1 REAR. No dedicated police-escort requirement, but superload movements require notifying all local emergency services of route/time/date prior to travel. Pilot vehicle: passenger car or two-axle truck min 60" wide, GVWR not over 14,000 lb, two-way comms, amber lights, staying within 1,000 ft of the load.

Travel Restrictions

Night travel: Generally allowed
Weekend travel: Generally allowed
Sunday travel: Generally allowed

Interstate: travel allowed 24/7 up to 18' wide. Non-interstate: 24/7 up to 10' wide, 150' long, or 15'6" high; loads exceeding those up to 12'6" wide may travel DAYLIGHT HOURS ONLY. Loads exceeding 18' wide, 150' long, or 17' high are NOT allowed weekend travel. No travel when a route is under severe driving conditions as determined by MDT. When pilot vehicles are required, the move must not delay traffic more than 15 minutes.

Holiday blackouts: Holiday/holiday-weekend travel is gated by dimension: INTERSTATE allowed 24/7 up to 18' wide (over 18' cannot travel on holidays/holiday weekends); NON-INTERSTATE allowed 24/7 up to 10' wide/150' long/15'6" high (over 10'-12'6" daylight-only; over 12'6" wide/150' long/15'6" high cannot travel on a holiday or holiday weekend). Specific named-holiday dates are on MDT's separate MT-PERMIT-RESTRICTIONS page (not enumerated in the FAQ source).

See how Montana compares to every state ›

Superload Thresholds

Width over: 18ft
Height over: 17ft
Length over: 150ft

A superload application is required when width exceeds 18'0" (216 in), height exceeds 17'0" (204 in), or length exceeds 150'0" (or when configuration/weights require MDT Bridge Bureau review). SUPERLOAD CLASS 1: over 18'-34' wide, over 17'-24' high, and/or over 150'-200' long (2-working-day decision). SUPERLOAD CLASS 2: over 34' wide, over 24' high, and/or over 200' long (5-working-day decision). No fixed superload weight threshold; overweight superloads via Bridge Bureau review. Superload notifications to mdtmcssuperload@mt.gov.

Estimated Permit Cost Verify before relying

$10 (0–100mi) / $30 (101–199mi) / $50 (200+mi)

Typical processing: 72-hour validity

⚠ Montana can adjust permit fees administratively without a statute amendment, so this carries real staleness risk despite the citation.

Source: §61-10-125 MCA — verify current fee with the permit office before budgeting a move.

Permit fee only — does not include escort/pilot-car service costs (market-rate, arranged separately) or third-party permit-service fees. This is an estimate for planning purposes, not a quote.

Get a Permit

Online portal: https://etrips.mtmdt.us/Login
Phone: 406-444-7262

Wide open roads with fewer urban restrictions.

Planning a move through Montana?

Enter your load's exact size to see whether it needs a permit or escort here, plan a truck-legal route, or find a transporter or escort.

Check my load in Montana Route Planner Find an Escort