How much cannabis can you buy in Montana? One ounce. That's the short answer for any adult 21+ at an adult-use dispensary, resident or visitor, and it's the figure written into state law. The fine print sits inside that ounce: caps on concentrates and edibles, package rules that changed on July 1, 2026, a 20% tax, and a list of places where none of it can be used. Here's the whole rulebook for a mountain-town trip, from Bozeman and Missoula to Helena and Butte.
The limit: one ounce, with two sub-limits
Montana law lets adults 21+ possess, purchase and transport 1 ounce or less of usable marijuana, with two conditions:
- No more than 8 grams in concentrated form
- No more than 800 mg of THC in edibles
Dispensaries are barred from completing a sale that would put a customer over those possession amounts. How a mixed basket of flower, a vape and a tin of gummies counts against the ounce is handled at the register. Ask the budtender before you build the cart, not after.
The same ounce is also the possession limit. A second dispensary stop on the same afternoon doesn't reset anything if the first bag is still in your backpack.
The package rules
Montana caps what goes in each package, separately from what you can carry:
- Flower: 1 ounce per package, with total THC no higher than 35%
- Edibles: no more than 100 mg of THC per package, and since July 1, 2026, no more than 5 mg per serving
- Capsules: no more than 100 mg per capsule and 800 mg per package
- Tinctures: no more than 800 mg per package
The 5 mg serving cap came from House Bill 636, passed in 2025. Visitors from states where 10 mg gummies are standard will find Montana's pieces half the size. Start low, go slow; the cap makes that the default.
Visitors buy like residents
There's no separate visitor limit. An adult 21+ with valid government ID gets the same ounce a Montanan does, at the same adult-use counter.
Medical cards are a different story. Montana issues registry cards only to Montana residents, and the law makes no provision for honoring a card from another state. Bring your home-state card and it buys you nothing extra; you shop under adult-use rules and adult-use taxes.
The tax
Adult-use cannabis carries a 20% state tax, and counties can add a local-option tax of up to 3% where voters approved one. Medical sales to Montana cardholders are taxed at 4%. Since May 2025, the state tax is calculated on the price after discounts and promotions.
Not every county sells
Adult-use sales exist only in what the Department of Revenue calls "green" counties, where a majority of voters supported the 2020 legalization initiative. In "red" counties, where a majority voted against it, adult-use sales are prohibited. The mountain towns sit in green territory: Bozeman, Missoula, Helena, Butte, Big Sky and the Flathead Valley towns all have licensed adult-use shops on the state's list. The dispensary directory shows what's where.
Within a green county, cities can still say no. Billings, the state's largest city, prohibits adult-use storefronts inside city limits, which is why the shops there sit just outside them.
Where it can't be used
Montana state law prohibits cannabis consumption in public places, and the statute adds a longer list:
- Vehicles. Drivers can't consume, and passengers can't smoke or consume in an enclosed vehicle while it's being driven. Driving under the influence is illegal.
- Public transportation, including trains and buses
- Hotel and motel rooms, for smoking, unless the room is designated a smoking room and rented to you
- Anywhere tobacco smoking is banned
- Schools, school buses and health care facilities
Then there's federal land. The Department of Revenue notes that marijuana possession and use remain prohibited under federal law on all federal lands and waters. In Montana that's a long list: Glacier and Yellowstone National Parks, the national forests that ring every mountain town, and Bureau of Land Management ground. Possession is the issue there, not just consumption.
Taking it home
The ounce doesn't travel. Carrying cannabis across a state line moves it into federal jurisdiction, and airport security runs on federal rules. Check the law of any state you drive into, and plan purchases so the trip ends with nothing left.
A quick reference
| Item | Montana rule | |---|---| | Age | 21+, valid government ID | | Total limit | 1 ounce | | Concentrate | 8 g within the ounce | | Edibles | 800 mg THC within the ounce | | Edible serving | 5 mg max (since July 1, 2026) | | Edible package | 100 mg max | | State tax | 20% adult-use | | Local tax | Up to 3% where adopted | | Out-of-state medical card | Not honored |
The regulator is the Department of Revenue's Cannabis and Alcohol Regulation Division, which publishes current rules and the licensed dispensary list at revenue.mt.gov. Mountain-town happenings are on the events hub.
FAQ
How much weed can you buy in Montana?
Adults 21+ can buy up to 1 ounce in total. Within that ounce, no more than 8 grams can be concentrate and no more than 800 mg of THC can be in edibles.
Can tourists buy weed in Montana?
Yes. Visitors 21+ with valid government ID can buy at adult-use dispensaries under the same 1-ounce limit as residents.
Does Montana accept out-of-state medical cards?
No. Montana issues medical cards only to residents, and visitors buy under adult-use rules and the 20% adult-use tax.
What is the tax on recreational weed in Montana?
The state tax on adult-use cannabis is 20%, and counties may add a local-option tax of up to 3% where voters approved one.
Can you bring weed into Yellowstone or Glacier?
No. Both are federal land, where marijuana possession and use remain prohibited under federal law regardless of Montana's legalization.
