You can drink in a parked RV, camper, or at your campsite in Montana without committing DUI. The risk starts when you are in a position to control a vehicle, or when you move it, in a place the DUI law covers. Because a motor home is both living space and vehicle, where that line falls takes some explaining. This page is part of our Montana DUI Guide and applies the rules from our page on actual physical control to camping.
Two Questions: Control and Place
Every DUI charge of this kind has to answer two questions. Was the person driving or in actual physical control of a vehicle? And, for an alcohol charge, was the vehicle on the ways of this state open to the public (MCA § 61-8-1002(1)(a), (b))? At a campsite, either one can be the weak point in the State's case.
Actual Physical Control in a Motor Home
Montana's statute does not define actual physical control. In State v. Sommers, 2014 MT 315, the Supreme Court told fact finders to consider the totality of the circumstances and listed factors. Here is how they map onto an RV. The right-hand column is our application, not language from the Court.
| Sommers factor | How it looks at a campsite |
|---|---|
| Where in the vehicle you were | In the bed, at the dinette, or outside by the fire points away from control. In the driver's seat points toward it. |
| Whether the key was in the vehicle, and where | A key in the ignition, or a running engine, is weighed against you. A key stored away is weighed for you. Neither decides the case. |
| Whether the engine was running | An engine running for heat or air conditioning is still a running engine. A separate generator is not the vehicle's engine. |
| Where the vehicle was parked and how it got there | Leveled, hooked up, awning out, and parked since the afternoon is strong evidence of camping. A motor home stopped crooked at the roadside is not. |
| Whether the vehicle could move, and how easily | Jacks down, slide-outs extended, hoses and power connected, or a trailer unhitched all bear on whether the vehicle could readily be driven. |
The Court also suggested a definition: a person is in actual physical control when the person "is not a passenger, and is in a position to cause the vehicle to move, or control the vehicle's movement in some manner or direction," and a person "need not be conscious." It held that a vehicle's ability to move is relevant. Put together, a person in the living area of a set-up motor home has good arguments, and a person dozing behind the wheel with the engine on has few.
Travel Trailers, Fifth Wheels, and Truck Campers
The code treats these as vehicles or vehicle-mounted structures: a travel trailer is "a vehicle" designed to provide temporary facilities for recreational, travel, or camping use, and a camper is a structure designed to be mounted in the cargo area of a truck (MCA § 61-1-101). But a trailer cannot move itself. The control question is really about the tow vehicle or the truck.
- Unhitched trailer. A person inside an unhitched trailer is not in a position to make any vehicle move. That is our reading of the Sommers definition. We found no Montana Supreme Court case on those facts.
- Truck camper. Sleeping in the camper box is different from sitting in the cab. The cab is where the controls are.
- Sleeping in the tow vehicle. This is the ordinary sleeping-in-your-car situation, and the ordinary risks apply.
Is a Campground a Way Open to the Public?
The definition covers "any highway, road, alley, lane, parking area, or other public or private place adapted and fitted for public travel that is in common use by the public" (MCA § 61-8-102(29)). The Supreme Court looks at all the surrounding circumstances, including whether it would be reasonable to expect a member of the public to be using the area (State v. Krause, 2021 MT 24).
- Public and commercial campgrounds. Entrance roads, loops, and parking areas are built for travel by whoever arrives. Expect them to be treated as ways open to the public. We did not find a decision specifically about an individual campsite pad.
- Dispersed camping off a forest road. A forest road open to public travel is likely covered. A spot well off it is a fact question.
- A friend's gated property. The Court has said the alcohol DUI statute does not apply to private property with limited access (State v. Lapointe, 2025 MT 124). See DUI on private property.
Remember that the provisions on drug-impaired driving apply anywhere within the state (MCA § 61-8-101(2)(b)).
The Drive In and the Short Move
Most campground DUI cases are not about sitting in a parked rig. They are about driving: arriving after drinking on the road, running to the store for ice, moving to a different site, or pulling out early in the morning. Our page on morning-after DUI covers that last situation.
Timing evidence runs both ways. Sommers allows a jury to infer control from the way a vehicle got where it is when the circumstances show the person drove it there while intoxicated. If the evidence instead shows you parked sober and drank afterward, that inference is not available.
Open Containers in an RV
Montana's open container law prohibits knowingly possessing an open alcoholic beverage container in the passenger area of a motor vehicle on a highway. It does not apply to a container in the immediate possession of a passenger in the living quarters of a camper, travel trailer, or motor home (MCA § 61-8-1026(2)(e)(ii)). Because the law applies on a highway, it is not aimed at a rig parked in a campsite. The fine for a violation is capped at $100. Our page on checkpoints and open containers has the details.
Camping in a National Park
In Glacier, Yellowstone, and other park areas, federal regulations replace the state rules. The park DUI regulation prohibits operating or being in actual physical control of a motor vehicle while impaired or at 0.08 or more (36 CFR § 4.23). The park open container rule exempts a container stored in the living quarters of a motor home or camper, and one in a vehicle "parked at an authorized campsite where the motor vehicle's occupant(s) are camping" (36 CFR § 4.14(c)). See DUI in national parks.
This page explains Montana and federal law in general as of October 2026. It does not tell you that any particular arrangement is safe, because these cases are decided afterward on all the circumstances. It is not legal advice about your specific case.