Adult-use cannabis has been legal in Montana since voters passed Initiative 190 in November 2020, and sales began in January 2022. Legal statewide is not the same as sold statewide. Counties where most voters opposed I-190 are "red" counties, and adult-use sales there are prohibited unless local voters later approve them. The Montana Department of Revenue currently lists 27 of them.
Montana has 56 counties and a great deal of empty road between them, so 27 is not a footnote. On the interstates the gaps are short. On the Hi-Line, across the center of the state and in the far southeast, they run for hours.
The rule, plainly
A red county bans adult-use sales. It does not ban possession. An adult 21+ may legally carry up to one ounce of flower, 8 grams of concentrate, or 800 milligrams of THC in edibles anywhere in the state, red counties included. Consumption is another matter: Montana state law prohibits cannabis consumption in public places everywhere, red or green.
What it means for your road trip: buy in a green county before the drive, carry it correctly, and do not expect a shop at the next exit.
The 27 counties
As listed by the Department of Revenue: Beaverhead, Broadwater, Carter, Chouteau, Daniels, Fallon, Fergus, Garfield, Golden Valley, Granite, Judith Basin, Liberty, McCone, Meagher, Musselshell, Petroleum, Phillips, Pondera, Powder River, Prairie, Stillwater, Sweet Grass, Teton, Toole, Treasure, Wheatland and Wibaux.
Every other county permits adult-use sales, though permitting is not the same as having a dispensary in every town. Check the dispensary directory for the stretch you are driving.
Corridor by corridor
I-90 east: Bozeman to Billings
Bozeman and Livingston sit in green counties. Then I-90 runs through Sweet Grass County, past Big Timber, and Stillwater County, past Columbus, and both are red. Sales resume in Yellowstone County at Laurel and Billings. The gap is about an hour of interstate.
I-94: Billings to North Dakota
East of Billings, I-94 enters Treasure County, which is red. Rosebud County, at Forsyth, and Custer County, at Miles City, are both green. Prairie County, at Terry, is red. Dawson County is green, which makes Glendive the last adult-use county on the interstate before Wibaux County, which is red, and the North Dakota line, where adult-use cannabis is not legal and where crossing with any cannabis is prohibited regardless.
I-15 north: Great Falls to the border
Great Falls is in Cascade County, a green county, and it is the last one northbound. Past it, I-15 crosses Teton, Pondera and Toole counties, all red, on the way to the Canadian border at Sweetgrass. Nothing crosses that border. Not a gram, not a pre-roll, not a sealed package from a licensed Montana shop.
I-15 south: Butte to Idaho
Butte and Silver Bow County are green. South of there, I-15 enters Beaverhead County, past Dillon, which is red all the way to Idaho, another state where crossing is prohibited.
I-90 west: Butte to Missoula
Mostly green, with one red county in the middle. Granite County covers the Drummond stretch of the interstate and Philipsburg to the south. Deer Lodge and Missoula are in green counties.
US-287: Helena to Bozeman
The direct route between Helena and Bozeman passes through Broadwater County and Townsend, which is red. It is a short gap, but it is the one most often missed, because it sits between two cities where shops are everywhere.
Central Montana
The middle of the state is largely red: Fergus County around Lewistown, plus Judith Basin, Wheatland, Golden Valley, Musselshell, Meagher and Petroleum. A drive from Great Falls to Billings through Lewistown or Harlowton crosses several of them back to back.
The Hi-Line and the far east
Along US-2, Phillips County at Malta, Liberty County at Chester and Toole County at Shelby are red. North of the highway, Daniels County is red. In the far east and southeast, Garfield, McCone, Fallon, Carter and Powder River are red, which takes in Jordan, Circle, Baker, Ekalaka and Broadus. Distances between towns of any kind run long out here, and towns with a dispensary are rarer still.
Carrying it legally through a red county
The Department of Revenue's vehicle rules apply everywhere, and they matter most on a long drive:
- Purchases stay in their unopened, original packaging
- Store them in a locked glove box or storage compartment, the trunk, a truck bed or cargo area, or behind the last upright seat in a vehicle without a trunk
- No one consumes in a moving vehicle, passengers included
- Montana's legal limit for driving is 5 nanograms of THC per milliliter of blood, and the safe number before a long drive is zero
Reservations and federal land
Seven Indian reservations lie within Montana's borders, governed by sovereign tribal nations with their own law. State legality and county color do not automatically carry over, so check the tribe's rules before assuming anything. Federal land is simpler: cannabis is prohibited on all of it, including national forests, national wildlife refuges, Glacier and Yellowstone.
The tax picture
Adult-use purchases carry Montana's 20 percent state tax. Counties may add a local option tax of up to 3 percent, and most of the green counties along the interstates have done so. Glendive, Miles City, Billings, Bozeman, Butte, Great Falls, Helena and Missoula all sit in counties on the local option list.
Compliance, quickly
- 21+ only at every dispensary; bring a valid government-issued photo ID, and expect most shops to want cash
- Verify licensed status through the Montana Department of Revenue Cannabis Control Division, now part of the department's CARD division, at revenue.mt.gov/card/cannabis, which also publishes the current county list and map
- Montana state law prohibits cannabis consumption in public places, which includes rest areas, pullouts and campgrounds open to the public
- Crossing a state line or the Canadian border with cannabis is prohibited, with no medical exception
- Start low, go slow with edibles, and never drive after consuming
Upcoming gatherings across the state are on the events hub.
