Yes, weed is legal in Montana for adults 21 and older, and it has been legal for medical patients since 2004. Voters approved recreational use in November 2020, and adult-use sales began on January 1, 2022.1Ballotpedia. Montana I-190, Marijuana Legalization Initiative (2020) You can buy from a licensed dispensary, grow a limited number of plants at home, and use cannabis in private. The rules on how much, where, and how tighten quickly once you step outside those basics.
What Adults Can Buy and Carry
If you are 21 or older, you can walk into a licensed Montana dispensary with a government-issued photo ID and buy cannabis. Out-of-state visitors can too.2Montana Department of Revenue. Purchasing Power and Identification Requirements at a Dispensary The possession and purchase limits are identical:3Montana State Legislature. Montana Code 16-12-106 – Personal Use and Cultivation of Marijuana — Penalties
- One ounce of flower
- Eight grams of concentrate
- 800 milligrams of THC in edibles
These are not cumulative. You can carry one ounce of flower or the equivalent in another form, not all three stacked together.
Growing at Home
Adults can grow up to two mature plants and two seedlings per person at their residence. If two or more adults share a household, the ceiling is four mature plants and four seedlings for the whole home, not per person.3Montana State Legislature. Montana Code 16-12-106 – Personal Use and Cultivation of Marijuana — Penalties Medical cardholders can grow four mature and four seedlings individually.
Plants have to be in a locked space on your private property, out of view from any public area. Anything you harvest beyond one ounce also has to stay in that locked space. Renters need written permission from the landlord before growing, and a landlord can say no.4Montana Department of Revenue. Know Before You Grow
Where You Can Use It
Cannabis use is restricted to private spaces. Under Montana law, consumption is prohibited in:5Montana State Legislature. Montana Code 16-12-108 – Limitations of Act
- Public places, indoors or outdoors
- Public transportation
- Hotels and motels, except in designated smoking rooms
- Schools and school buses, from preschool through postsecondary
- Healthcare facilities
- Correctional facilities
- Anywhere tobacco smoking is banned
Smoking in a public place carries a civil fine of up to $50.3Montana State Legislature. Montana Code 16-12-106 – Personal Use and Cultivation of Marijuana — Penalties Violations at schools, healthcare facilities, and other restricted sites can carry more.
You can give cannabis to another adult 21 or older, or to a registered medical cardholder, so long as no money or compensation changes hands and you stay within the possession limits.3Montana State Legislature. Montana Code 16-12-106 – Personal Use and Cultivation of Marijuana — Penalties Giving cannabis to anyone under 21 who is not a registered patient is illegal.5Montana State Legislature. Montana Code 16-12-108 – Limitations of Act
Driving After Using Cannabis
Montana sets a per se THC limit of 5 nanograms per milliliter of blood. Meet or exceed that number and you have committed a DUI as a matter of law, with no separate proof of impairment required.6Montana State Legislature. Montana Code 61-8-1002 – Driving Under Influence You can also be charged under the general impairment standard at any blood level.
A first cannabis DUI can bring up to six months in jail and a fine of $600 to $1,000.7Montana State Legislature. Montana Code 61-8-1007 – Penalty for Driving Under Influence — First Through Third Offenses With a passenger under 16 in the car, the minimum fine doubles to $1,200 and jail time can reach a year. A conviction triggers mandatory license suspension or revocation, and second and third offenses carry steeper minimums. Consuming cannabis in a moving vehicle is prohibited whether you are the driver or a passenger.
What Happens If You Go Over the Limit
Between one and two ounces of flower (or between eight and 16 grams of concentrate) is a civil infraction. The marijuana is forfeited, and the fines escalate:3Montana State Legislature. Montana Code 16-12-106 – Personal Use and Cultivation of Marijuana — Penalties
- First violation: up to $200 or up to 4 hours of community service
- Second violation: up to $300 or up to 6 hours of community service
- Third or later violation: up to $500 or up to 8 hours of community service
Cross two ounces and the picture changes completely. Possession over two ounces is a felony punishable by up to five years in prison and a fine of up to $45,000. One ounce separates a $200 civil ticket from a felony.
The Medical Program
Medical cardholders get higher purchase limits, larger home-cultivation allowances, and a much lower tax rate. To qualify, you must be a Montana resident with a debilitating condition documented by a licensed physician (MD or DO), and the recommendation must be signed within 60 days of your application.8Montana Department of Revenue. Cardholder Information Minors can qualify with a guardian’s involvement and a separate physician form.
Qualifying conditions include cancer, glaucoma, HIV/AIDS, cachexia, severe chronic pain, intractable nausea, epilepsy, multiple sclerosis, Crohn’s disease, painful peripheral neuropathy, central nervous system disorders causing spasticity or spasms, hospice admission, and PTSD.
Applications go through the Montana Department of Revenue’s TransAction Portal. The state fee is $20 for a new card or renewal and $10 for a replacement. The physician evaluation is paid separately to the doctor.
A cardholder can possess up to one ounce at a time, purchase up to five ounces per month, and buy no more than one ounce in a day.9Montana State Legislature. Montana Code 16-12-515 – Legal Protections — Allowable Amounts Patients whose conditions require more can petition the department for an exception with physician support. Montana does not recognize medical cards from other states.
Taxes at the Register
Montana taxes cannabis only at retail. Recreational purchases carry a 20% state tax; medical purchases are taxed at 4%.10Montana Department of Revenue. Cannabis Tax Counties can add an optional local tax of up to 3%. On a $100 purchase, that is $20 in state tax recreationally versus $4 with a card, which is the single biggest financial reason to pursue medical certification if you qualify.
Cannabis and Your Job
Montana is unusual in offering statutory protection for off-duty marijuana use. Employers generally cannot refuse to hire, fire, or discipline you for using a lawful product on your own time.11Montana State Legislature. Montana Code 39-2-313 – Discrimination Prohibited for Use of Lawful Product During Nonworking Hours — Exceptions
The exceptions matter. Employers can still act if cannabis use affects job performance, poses a safety risk, or conflicts with an occupational requirement. Companies with established substance abuse policies or testing programs can enforce them. And the state statute does not override federal drug testing rules for federally regulated jobs like commercial trucking and aviation.
Federal Law Still Applies
Cannabis remains a Schedule I controlled substance federally, and that creates traps a Montana resident can hit without realizing it.
Federal Land
Possessing or using marijuana on any federal property is illegal, including national parks, national forests, Bureau of Land Management land, and military installations.12National Park Service. Marijuana and Other Substances – Bering Land Bridge National Preserve Given how much of Montana is federal land, the line between state and federal jurisdiction is not always obvious from a trail or campsite.
Firearms
Federal law bars anyone who uses a controlled substance, including marijuana, from possessing firearms or ammunition.13Office of the Law Revision Counsel. 18 U.S. Code 922 – Unlawful Acts ATF Form 4473, filled out at any licensed firearm purchase, asks directly whether you are an unlawful user of any controlled substance and warns that marijuana use is unlawful federally even in states where it has been legalized. A dishonest answer is itself a federal crime.
State Lines
Taking cannabis across a state border is a federal offense, even if the destination state has also legalized it. Buy in Montana, use in Montana.
Delta-8 and Hemp-Derived THC
Synthetic marijuana products are banned outright. Any cannabinoid product above 0.3% THC can only be sold through a licensed dispensary or manufacturer, not a gas station, convenience store, or smoke shop.14Montana State Legislature. Montana Code 16-12-117 – Synthetic Marijuana Products Prohibited — Restriction on Sale of Marijuana Products Products at or below 0.3% THC sold outside that system are capped at 0.5 milligrams of THC per serving and 2 milligrams per package. Unprocessed hemp flower is exempt from those dosing limits. In practical terms, most Delta-8 and hemp-derived THC products you might expect to see in a convenience store elsewhere are channeled into the licensed dispensary system in Montana.