Montana Marijuana Laws (2026): Possession, Limits and Where to Buy

By James Buddsey · Updated November 4, 2026

Yes. Under Montana marijuana laws, adults 21 and older can legally possess and use up to 1 ounce of marijuana, including no more than 8 grams of concentrate and 800 milligrams of THC in edibles, and can buy it at licensed dispensaries in counties that allow adult-use sales. Adults may grow 2 mature plants and 2 seedlings at home, public use carries a civil fine of up to $50, and adult-use purchases are taxed at 20% plus up to 3% in some counties, as of October 2026.

Montana voters legalized adult-use marijuana with Initiative 190 in November 2020, and the Legislature has rewritten the rules several times since, most recently in 2025. This guide gives residents and visitors the current rules, linked to the Montana Code Annotated (MCA) and Department of Revenue pages behind them. It is general information, not legal advice.

Montana Cannabis Laws at a Glance

Is Marijuana Legal in Montana?

Yes. Initiative 190 was approved on November 3, 2020, according to the history note on MCA 16-12-106. Under the Department of Revenue FAQ, adults 21 and older have been allowed to possess and use up to 1 ounce since January 1, 2021, and to buy at licensed dispensaries since January 1, 2022. In 2021 the Legislature amended the initiative with HB 701, the Montana Marijuana Regulation and Taxation Act, which set the tax rates still in use, according to a Legislative Fiscal Division overview.

The law lives in Title 16, chapter 12 of the MCA. The Montana Department of Revenue licenses and inspects the industry and runs the medical registry. Marijuana remains illegal under federal law for adult use, which matters in national parks, national forests and at airports. See our guide to federal marijuana law in 2026.

How Much Marijuana Can You Possess in Montana

Under MCA 16-12-106, an adult 21 or older, or a registered cardholder, may possess, buy, use and transport:

• Up to 1 ounce of usable marijuana, and within that ounce
• no more than 8 grams of concentrate, and
• no more than 800 milligrams of THC in edible products

Adults may also give up to 1 ounce to another adult 21 or older as long as no money changes hands, and may buy or possess paraphernalia.

Penalties for going over the limit

Possession with intent to deliver more than 1 but less than 2 ounces, or more than 8 but less than 16 grams of concentrate, is a civil violation under MCA 16-12-106(7). The marijuana is forfeited, and the fine is up to $200 for a first violation, $300 for a second and $500 after that, or 4, 6 or 8 hours of community service instead.

Above the amounts chapter 12 permits, the general drug statute applies. MCA 45-9-102 sets a maximum of 5 years in state prison and a $5,000 fine for criminal possession of dangerous drugs, with a presumption of a deferred sentence for a first violation.

Under 21

People under 21 who are not registered cardholders face the penalties in MCA 45-5-639. A first offense carries a fine of $100 to $300, 20 hours of community service and a substance abuse information course. Penalties rise with each later offense.

Where You Can and Cannot Use Marijuana in Montana

Smoking marijuana in a public place, other than an area licensed for it, is subject to a civil fine of up to $50 under MCA 16-12-106(4). MCA 16-12-108 lists the other limits.

Not allowed

• Public places, trains, buses and other public transportation
• Anywhere tobacco smoking is banned
• Hotel and motel rooms, unless the room is a designated smoking room
• School grounds, preschools, colleges and school buses
• Health care facilities and correctional facilities
• Moving vehicles, including passengers
• Federal land and water, including Glacier and Yellowstone national parks, per the Department of Revenue

Use is allowed on private property with the owner’s permission, and owners may ban it. Leases signed after January 1, 2021, may not bar a tenant from possessing marijuana and consuming it by means other than smoking, unless federal law or federal funding requires it. Employers need not accommodate marijuana use.

Buying Marijuana in Montana: Dispensaries and County Rules

Where you can buy depends on the county. The Department of Revenue uses a color code:

• Green counties allow adult-use sales. Any adult 21 or older can buy there.
• Red counties do not allow adult-use sales. Dispensaries there may sell only to medical cardholders.
• Blue marks a county that has adopted a local option tax.

A county’s status can change through a later local election. Under SB 27 (2025), dispensaries in green counties may sell both medical and adult-use products, while red counties remain medical-only, according to the Department of Revenue’s 2025 legislative summary.

• Age: 21 or older for adult-use purchases. People under 21 may not enter a dispensary without a registry card or worker permit.
• Hours: Licensed dispensaries may operate only from 9 a.m. to 8 p.m. daily, under MCA 16-12-207(11) and the department.
• Check the license: A legal store appears on the department’s monthly Licensed Dispensary List and displays its site certificate.

Product limits

Adult-use flower may contain no more than 35% total THC, and concentrates are capped at 800 mg per package, per the department’s FAQ. Since July 1, 2026, under HB 636, edibles are limited to 5 mg THC per serving and 100 mg per package.

Medical Marijuana in Montana

The medical program is run by the Department of Revenue. According to its cardholder information page:

• Eligibility: Montana residents with a recommendation for a debilitating medical condition from a Montana-licensed MD or DO, signed within 60 days of applying.
• Fees: $20 for a new or renewal card, $10 for a replacement.
• Purchase limits: up to 1 ounce of flower per day and 5 ounces per month, which can be raised to 8 ounces per month on a petition signed by the cardholder’s physician. One ounce equals 800 mg of THC in infused products or 8 grams of concentrate.
• Designated purchasers: up to two adults 21 or older.
• Tax: medical purchases are taxed at 4% instead of 20%.

We found no provision recognizing out-of-state medical cards.

Growing Marijuana at Home in Montana

Under MCA 16-12-106:

• Adults 21 and older may grow 2 mature plants and 2 seedlings at a private residence.
• Registered cardholders may grow 4 mature plants and 4 seedlings.
• The grower must own the home or have the owner’s written permission.
• Plants and harvested marijuana must be kept in a locked space and not visible from a public place.

Plants that can be seen from a public place, or marijuana stored outside a locked space, bring a civil fine of up to $250 and forfeiture.

Driving and Marijuana in Montana

Driving with 5 ng/mL or more of THC in the blood, excluding inactive metabolites, is DUI under MCA 61-8-1002. Drivers under 21 commit DUI with any amount of THC. Impairment by any drug can also be charged without a test number.

How you carry it matters too. Under MCA 61-8-1027, as explained in the department’s Know Before You Go page, marijuana in a personal vehicle must be in a locked glove box, the trunk, a truck bed or cargo area, behind the last upright seat or in a closed container away from the occupants. A violation is a civil offense with a fine of up to $100, and it cannot be recorded on your driving record.

Crossing State Lines, Airports and Federal Land

• Other states: The Department of Revenue says carrying marijuana across state lines is prohibited under any circumstances, including medical marijuana, and that applies even to a neighboring state. See our Wyoming marijuana laws guide and North Dakota guide.
• Flying: The TSA follows federal law and refers cannabis found at screening to police. Carrying cannabis on any flight is illegal under federal law.

Montana Marijuana Taxes in 2026

According to the Department of Revenue, the state tax is 20% on adult-use sales and 4% on medical sales, charged at retail. Counties may add a local option tax of up to 3% on medical, adult-use or both. Custer and Jefferson counties added 3% taxes effective April 1, 2025. Since SB 74 (2025), the tax is based on the retail price after discounts and promotions. Cardholders who grow their own are not taxed.

Hemp, Delta-8 and Synthetic Cannabinoids

Montana bans synthetic cannabinoids in its marijuana market. HB 49 (2025) added storage to the prohibited activities and barred synthetic cannabinoid products from adult-use dispensaries, per the department’s 2025 summary. Department rule ARM 42.39.401 requires every cannabinoid in a marijuana product to be naturally occurring.

On hemp, SB 375 (2025) says a hemp product containing total delta-9 THC may not be sold to a consumer in Montana unless the FDA authorizes it as a food or drug. Federal law is tightening too: a 2025 law caps hemp products at 0.4 mg total THC per container and excludes synthesized and converted cannabinoids, effective November 12, 2026 for cannabinoids the plant cannot naturally produce, such as THC-O, and December 11, 2026 for everything else, including delta-8.

Clearing Old Marijuana Convictions

MCA 16-12-113 lets people with convictions for acts that are now legal, or now carry a lower penalty, petition the sentencing court for expungement or resentencing. The court presumes eligibility unless the county attorney shows otherwise. Relief is not automatic; you must file a petition.

What Changed in Montana Marijuana Law Recently

• July 1, 2026: HB 636 edible limits (5 mg per serving, 100 mg per package) and HB 792 labeling and point-of-sale warning rules took effect.
• 2025 session: SB 27 froze new licensed premises until the moratorium ends July 1, 2027; SB 74 changed the tax base; HB 49 tightened the synthetic cannabinoid ban; SB 375 restricted hemp products with delta-9 THC.
• Federal (2026): In April 2026 the Justice Department moved marijuana held under a state medical marijuana license, and FDA-approved marijuana products, to Schedule III. Adult-use marijuana remains in Schedule I, and a broader rescheduling proceeding was stayed on September 29, 2026.

Montana Marijuana Laws FAQ

More State and Federal Marijuana Guides

See all state cannabis law guides and our federal marijuana law guide. Neighbors and nearby states: Wyoming, North Dakota, Washington and Oregon. Driving west to Spokane? See Washington dispensaries.

General information about Montana cannabis law as of October 2026, not legal advice.