Possession and use
Adults 21 and over may possess up to one ounce of marijuana. The state visitor checklist gives purchase equivalents, including eight grams of concentrate or 800 milligrams THC in infused products. Public use and use on federal land are prohibited.
Montana's visitor checklist gives equivalent purchase forms: one ounce of flower, eight grams of concentrate, or 800 milligrams THC in edibles or other specified products per transaction. Product form matters because an ounce of concentrate is not treated as an ounce of flower. Medical cardholder quantities follow separate rules.
Medical access
Montana's medical program is for registered cardholders. The Department of Revenue says an applicant must be a Montana resident with a recent Montana-licensed physician statement; a visiting out-of-state card alone does not establish eligibility for Montana medical purchasing. Cardholders may buy up to one ounce of flower daily and five ounces monthly, with a petition route for a higher monthly limit.
Adults 21 and over who visit from another state may instead use licensed adult-use stores in counties permitting those sales. The adult-use one-ounce transaction and possession rules then apply. This route is separate from medical-card taxation and higher cardholder monthly purchase rights.
Home cultivation
A Montana resident adult 21 or older may grow two mature plants and two seedlings at a private residence; a registered medical cardholder may grow four mature plants and four seedlings. Visitors cannot use the adult personal-grow allowance. The grower must own the residence or have written owner permission, and plants must be locked and hidden from public view.
When multiple adult consumers share a residence, the limit is four mature plants and four seedlings there. When multiple registered cardholders share one, the limit is eight mature plants and eight seedlings. The Department of Revenue does not spell out how a mixed adult/cardholder household combines those categories, so the two residence ceilings should not be added together.
Buying legally
Licensed adult-use sales began January 1, 2022, but not in every county. Montana distinguishes counties allowing adult-use commerce from those limiting sales to medical customers. Visitors aged 21 and older should use the state's license and county information before planning a purchase.
Montana's county distinction affects where adult-use businesses may sell. The state's visitor checklist tells shoppers to check the current county map and licensed dispensary before travel. A medical-only store in a county that restricts adult commerce cannot be treated as an adult-use retailer merely because statewide possession is lawful.
Taxes
Montana imposes a 20% retail tax on adult-use marijuana and 4% on medical sales. Counties may add a local option tax up to 3% on either category. The department says personal homegrown cannabis is not taxed.
Travel and transport
The Department of Revenue instructs drivers to leave purchases in unopened original packaging. It says crossing state lines in a motor vehicle with either adult-use or medical cannabis is prohibited; a medical card creates no exception. Never drive while impaired.
Sources and remaining checks
We checked the sources below on the date shown above. Rules may have changed since then. Check the current rules before making a decision, and read the remaining questions noted in this guide.
- Montana DOR cannabis FAQ. Possession, 2022 sales, home grow, county limits.
- Montana DOR 2026 visitor checklist. Visitor purchase and resident-only growing.
- Montana DOR cannabis tax. 20% adult, 4% medical, up to 3% local.
- Montana DOR road transport guidance. Packaging and interstate prohibition.
- Montana DOR cardholder information. Medical purchase limits; Montana residency for card application.
- Montana Department of Revenue Know Before You Grow. Explicit adult and medical per-person counts and shared-residence caps.
- Montana Code Annotated 2025 section 16-12-106. Personal cultivation, twice-individual residence maximum, security and written owner permission.
No professional legal review is claimed. Check official sources and the verification notes below.