Quick answer: Yes, marijuana is legal in Montana for adults 21 and older, and the state also has a medical program. Adults can possess up to 1 ounce of flower, 8 grams of concentrate or 800 mg of THC in edibles. Home growing is allowed: 2 mature plants and 2 seedlings per adult, with a household cap of 4 and 4.

Last verified: October 20, 2026, against the Montana Department of Revenue, Cannabis and Alcohol Regulation Division. Laws change, so check the official site before you travel or buy.

Who can buy?

Adults 21 and older with a qualifying ID can buy adult-use marijuana at a licensed dispensary. You don’t have to live in Montana. A separate constitutional amendment, CI-118, set the age at 21. Registered medical cardholders can buy at any licensed dispensary, and some of them are younger than 21.

Where can you buy?

Only at dispensaries licensed by the Cannabis and Alcohol Regulation Division (CARD). Montana has a twist that surprises visitors: green counties and red counties.

• Green counties voted for I-190 in 2020, so adult-use sales are allowed there.
• Red counties voted against it, so dispensaries there can only sell to medical cardholders.

Before you drive across the Big Sky State hoping to shop, check the department’s licensed dispensary list. It’s updated monthly and shows whether each store can sell adult-use. Licensed dispensaries can only open from 9 a.m. to 8 p.m. If a “dispensary” is selling at midnight, skip it.

Adult-use purchases carry a 20% state tax, and counties can add up to 3% more.

How much can you buy or possess?

• up to 1 ounce of marijuana flower,
• up to 8 grams of concentrate, and
• marijuana products, including edibles, with up to 800 mg of THC.

Montana also caps potency. Adult-use flower can’t exceed 35% total potential THC, and an edible serving is capped at 10 mg of THC, with no more than 100 mg per package. Medical cardholders can buy up to 1 ounce of flower a day and up to 5 ounces a month, and a petition can raise that monthly limit.

Can you grow your own?

Yes. Adults 21+ can grow up to 2 mature plants and 2 seedlings for personal use at a private residence. A household tops out at 4 mature plants and 4 seedlings, no matter how many adults live there. Registered medical cardholders can grow up to 4 mature plants and 4 seedlings. Plants can’t be visible to the public, and landlords can say no.

Where can you smoke?

Only in private. Using marijuana in public is prohibited, and so is using it at a dispensary. Montana dispensaries don’t allow on-site use, or even opening a package on the premises. Federal land is off-limits too, and Montana has a lot of it: Glacier, Yellowstone and huge national forests.

Can you drive after using?

No. This is one place where Montana is stricter than many legal states. Montana has a per se limit of 5 nanograms of delta-9 THC per milliliter of blood. If you test at or above that level, you can be charged with DUI even if you seemed fine. You can also be charged at lower levels if you’re actually impaired. Regular users can stay above 5 ng/mL longer than they’d expect, so don’t count on “feeling fine.”

Can you take it out of state?

No. Taking marijuana across state lines is a federal crime. That goes for Idaho, Wyoming and the Dakotas, and for the Canadian border.

Federal context, as of October 2026: recreational marijuana is still a Schedule I drug federally. In April 2026, state-licensed medical marijuana and FDA-approved products moved to Schedule III, and broader rescheduling was paused on September 29, 2026. A November 2025 federal hemp law takes away legal status from intoxicating hemp-THC products such as delta-8 and THCA flower, with its main provisions taking effect December 11, 2026.

Can your employer fire you?

Generally yes. Montana’s marijuana law doesn’t require employers to allow use, and employers can keep drug-free workplace policies. Workers in jobs covered by federal rules, such as commercial drivers, still face federal testing. Read your handbook before you assume you’re covered.

Penalties, briefly

• Possessing more than 1 oz up to 2 oz: civil infraction, with a fine of up to $200 or community service the first time.
• Possessing more than 2 oz: this can be charged as a felony.
• Possessing 8 to 16 grams of concentrate: civil infraction. Larger amounts can be felonies.
• Growing above the limit, selling without a license, or selling to minors: criminal charges.
• Driving at 5 ng/mL THC or higher: per se DUI.

Compare Montana with nearby states on our marijuana law hub.

Montana marijuana law FAQ

Is recreational weed legal in Montana?

Yes. Montana voters legalized adult-use marijuana in 2020, and sales started January 1, 2022. Adult-use sales are allowed only in “green” counties that voted yes. Other counties allow medical sales only.

How much weed can you buy in Montana?

Adults 21+ in Montana can possess and buy up to 1 ounce of flower, 8 grams of concentrate or products containing up to 800 mg of THC. Medical cardholders can buy up to 1 ounce a day and 5 ounces a month.

What is the THC driving limit in Montana?

Montana has a per se DUI limit of 5 nanograms of delta-9 THC per milliliter of blood. Drivers at or above that level can be charged with DUI even without other signs of impairment.

How many plants can you grow in Montana?

Adults 21+ in Montana can grow 2 mature plants and 2 seedlings, with a household maximum of 4 mature plants and 4 seedlings. Registered medical cardholders can grow 4 mature plants and 4 seedlings.

Can tourists buy marijuana in Montana?

Yes. Visitors 21 and older can buy at licensed adult-use dispensaries in Montana’s green counties with a valid ID. Taking it out of Montana is illegal under federal law.