Montana voters legalized weed for adults 21 and older in November 2020, and the way that vote split, county by county, still decides where you can buy it. Initiative 190 passed statewide. But in counties where most voters said no, adult-use dispensaries can’t open unless local voters later approve them. So the most useful question in Montana isn’t “is it legal?” It’s “which county am I in?”
The rest is statewide: what you can carry and grow doesn’t depend on the county, and licensed adult-use sales have run since January 2022. But in a “red” county, the dispensary down the road may only be allowed to serve medical cardholders.
Buying weed in Montana: green counties and red counties
The Department of Revenue’s shorthand is simple. “Green” counties, where a majority voted for I-190, allow adult-use sales. “Red” counties, where a majority voted against it, don’t, and a marijuana business can’t operate there until the local jurisdiction approves that license category and the state licenses it. Medical businesses that were already licensed in red counties can keep operating as medical at their existing premises, and a 2025 law kept that structure in place: green-county dispensaries can sell both medical and adult-use, red-county ones medical only.
The map can change. Voters can petition for a local election to allow or prohibit categories of cannabis businesses, and some cities have different rules from surrounding counties. The Department of Revenue now publishes an actual county-by-county map and status table, updated for later local votes. As of its current list, Beaverhead, Granite, Broadwater and Toole prohibit adult-use sales, while Glacier allows them. A county marked blue has approved an optional local cannabis tax; that color alone doesn’t tell you whether adult-use sales are legal. If you’re driving across Montana, check the county’s sales status and the store’s adult-use license before making a detour.
At the register, adult-use purchases are taxed at 20% and medical at 4%, and counties can add up to 3% more. Edibles top out at 100 mg of THC a package and 5 mg a serving.
The market rules, if you want them
A local prohibition vote takes effect on the 90th day after the election. Since a 2025 change, the state tax is based on the price after discounts and promotions. The edible caps (100 mg of delta-9 THC per package, 5 mg per serving, with a ±10% variance) apply to ingestible products sold since July 1, 2026. Synthetic cannabinoid products are barred from adult-use dispensaries, and new licenses are on hold under a moratorium that now runs to June 30, 2027. In September 2026, the department reported $25,577,747 in adult-use sales and $2,477,682 in medical sales.
How much you can carry: an ounce, then civil fines
The numbers, and who they apply to
- PossessionAdults 21+ and registered cardholders
- 1 oz usable marijuana; within it, max 8 g concentrate and 800 mg THC in ediblesApplies anywhere you carry it. More than that isn't protected by the law.Source
- Home growAdults 21+
- 2 mature plants + 2 seedlingsOnly at a private residence, in a locked space that can't be seen from a public place. You need to own the home or have the owner's written permission. A residence may have no more than double the per-person limit at one time.Source
- Home growRegistered medical cardholders
- 4 mature plants + 4 seedlingsSame conditions as adults (locked, not visible, owner's permission), and the same cap of double the per-person limit per residence.Source
- RetailRegistered medical cardholders
- 1 oz flower a day; 5 oz a month (up to 8 oz a month by physician petition)Equivalents: 1 oz flower = 800 mg THC in infused products or 8 g/8 mL concentrate.Source
- DrivingAll drivers
- 5 ng/mL THC (active, excluding inactive metabolites) is a per se DUIYou can also be charged with DUI for being under the influence, regardless of the number.Source
- RetailAdult-use products sold from July 1, 2026
- Max 100 mg delta-9 THC per package and 5 mg per serving for ingestible productsSet by a 2025 law; a ±10% variance applies.Source
- RetailAdult-use edibles and ingestibles
- 5 mg THC per serving, 100 mg per packageRetail product limits effective July1 2026, separate limits for capsules, patches and concentrates.Source
Adults 21 and older, and registered cardholders, can possess and use up to 1 ounce of usable marijuana. Within that ounce, no more than 8 grams can be concentrate and no more than 800 mg of THC can be in infused products you swallow in solid form, like gummies or chocolate. You can also give up to an ounce to another adult, as long as no money changes hands.
Going a little over is a civil matter, not a crime. Having more than an ounce but less than 2 ounces of flower, or more than 8 but less than 16 grams of concentrate, means forfeiting it and a civil fine (or community service) that steps up with each violation. The same applies to giving 1 to 2 ounces to another adult for free. Beyond those amounts, you’re outside the cannabis law altogether and under Montana’s general dangerous-drug possession statute, which carries up to 5 years in prison and/or a $5,000 fine. A first offense there is presumed eligible for a deferred sentence.
The over-the-limit fines, if you want them
Under MCA 16-12-106(7), possession, production, delivery without consideration to someone 21 or older, or possession with intent to deliver more than 1 oz but less than 2 oz (or more than 8 g but less than 16 g of concentrate), outside the medical part, brings forfeiture plus the person’s choice of a civil fine of up to $200 or up to 4 hours of community service for a first violation, up to $300 or 6 hours for a second, and up to $500 or 8 hours for a third or later. Above that, MCA 45-9-102 applies.
Where you can use it: not in public, and the lease twist
Not in public. The law doesn’t permit using marijuana in a public place (except where the department allows it), on public transportation or anywhere tobacco smoking is banned. And you can’t have it at all, let alone use it, on school or college property, on a school bus, in a health care facility or on correctional facility grounds. Smoking in public outside a department-licensed area can bring a civil fine of up to $50, and we know of no department-licensed lounge to go to.
Private property is a different matter, with one twist that renters should know. Owners, managers and occupants can prohibit or regulate marijuana use on their property. But a lease signed after January 1, 2021 can’t ban a tenant from having it or using it in ways other than smoking, unless federal law or federal funding requires it. In hotels and motels, smoking is allowed only in a designated smoking room, and the property can still say no to use altogether.
Growing your own: two plants, locked and unseen
Montana is a real grow state. Adults 21 and older can cultivate up to two mature plants and two seedlings at a private residence; registered cardholders can grow four mature plants and four seedlings. Montana defines a seedling as a plant with no flowers that’s less than 12 inches tall and 12 inches across, so anything bigger counts as mature. However many growers live there, a single residence can’t have more than twice the individual limit at the same time. For adult-use growers, that’s four mature plants and four seedlings per house.
Three conditions come with it. Plants have to be in a locked space that can’t be seen from a public place. You have to own the residence or have the owner’s written permission, so renters need it in writing before they set up. And the harvest gets the same treatment: any harvested marijuana over 1 ounce has to be kept locked and out of public view. Visible plants or unlocked storage carry a civil fine of up to $250 and forfeiture.
Two mature plants isn’t many, so make them count. Early topping and training and a longer veg let two plants fill a space that would otherwise hold four. The harder rule is “locked and unseen.” Indoors, a lockable grow box handles it by design. Outdoors, plants have to stay locked away and invisible from anywhere public all season, so a tall plant by a chain-link fence is a problem by August. A mother plant kept for clones will almost certainly be over the seedling size, so she counts as one of your mature plants, and if you share a house with other growers, everyone’s plants count against the same residence ceiling.
At harvest, plan where the jars go before you chop. Two healthy plants can finish well above an ounce dried, and everything over that ounce has to be locked up, so a lockable cabinet for drying and curing is part of the setup, not an afterthought.
Visiting, driving and crossing borders
Visiting Montana?
- Buying
- Visitors, with limitsMontana official 2026 visitor guide welcomes adults 21+ with ID to licensed adult-use retailers, but county-level adult-use sales bans still apply.
- Carrying
- Adults 21+ fall under the same 1 oz limit whatever their residency; the statute applies to persons 21 or older.
- Using it
- Not in public. Owners, including hotels, can ban use; hotel smoking is limited to designated smoking rooms where allowed at all.
- Medical card from home
- IllegalMontana's medical card is for Montana residents only, and the law has no provision recognizing other states' cards.
- Getting around
- In the car, keep anything opened or home-grown in a locked glove box, the trunk, cargo area or behind the last upright seat; unopened store packaging can ride in the cabin. Taking marijuana across state lines is prohibited, even with a medical card.
A visitor 21 or older can buy cannabis from a Montana adult-use licensed store with valid government-issued photo ID. The Department of Revenue even publishes a 2026 visitor cannabis checklist saying so. Don’t head to just any medical dispensary: Montana’s county-by-county adult-use restrictions still determine where a recreational shop may sell. Montana medical cards are reserved for state residents, and out-of-state medical cards don’t automatically substitute for one.
In the car, the rule is about the passenger area. Store-bought product in its unopened original packaging can ride anywhere. Anything opened, or home-grown, has to go in a locked glove box or storage compartment, the trunk, a truck bed or cargo area, or behind the last upright seat if there’s no trunk. Breaking that is a civil offense with a fine of up to $100 that doesn’t go on your driving record. Nobody can use marijuana while driving, or smoke or consume it in the passenger seat of the enclosed part of a moving vehicle.
Montana has a THC number for driving. It’s an offense to drive with an active THC level (inactive metabolites don’t count) of 5 ng/mL or more in your blood or another bodily substance, and you can also be charged for driving under the influence regardless of the number.
Leave it in Montana when you go. The Department of Revenue itself says taking marijuana across state lines is prohibited under any circumstances, medical included, and that goes double for the Canadian border; the federal box below has what that crossing can cost.
Medical marijuana
The medical card is for Montana residents with a debilitating medical condition, and the definition of resident excludes anyone claiming residence in another state. You need a recommendation from a Montana-licensed physician (MD or DO) dated within 60 days of applying; minors need two physicians unless the treating physician is an oncologist, neurologist or epileptologist. A new card or renewal costs $20 and lasts up to a year from approval, unless the physician sets a shorter period. The Department of Revenue’s cardholder page has the steps.
What a card adds: double the home grow (see growing your own), a 4% tax instead of 20%, and dispensary access in red counties. Cardholders can buy up to an ounce of flower a day and 5 ounces a month, which a physician-signed petition can raise to 8, and can designate up to two purchasers aged 21 or older. The everyday possession limit is the same 1 ounce adults have.
There’s one detail that can throw off a checkout: Montana limits ingestible adult-use marijuana products to 5 mg THC per serving and 100 mg per package as of July 1, 2026. A capsule or patch has different category limits, and some concentrates carry a separate 800 mg THC package ceiling. The state’s retail sales limits page lists those distinctions. A 10 mg edible from an older product review is not the current Montana adult-use single serving limit.
What can still get you in trouble
Under 21, it’s off-limits. People under 21 can’t buy, use, possess or transport marijuana unless they’re registered cardholders, or 18-or-older employees of a licensed business possessing or transporting it at work.
Gas-station THC isn’t a workaround. Since May 2025, no hemp product containing delta-9 THC can be sold to consumers in Montana unless the FDA has authorized it as a food or drug. That covers gummies, but also hemp vapes, pre-rolls and anything else meant to be eaten, smoked or vaped.