Montana

Overview

Montana voters legalized adult-use cannabis through I-190 in 2020, and retail sales began in 2022. Adults 21+ may possess up to one ounce. Home grow is limited to two mature plants and two seedlings per adult, with a cap of four of each per residence. The Cannabis Control Division of the Department of Revenue regulates licensees. Counties that voted against I-190 do not allow storefronts unless local voters approve them.

Last reviewed October 2026. General information, not legal advice.

What's Legal

Public consumption is a civil infraction; consumption is allowed on private property.

Possession Limits

1 oz in public

Home Growing

Up to 2 mature plants and 2 seedlings per adult; max 4 mature plants and 4 seedlings per residence

Driving and Cannabis

Driving while impaired by cannabis is illegal in Montana, as it is in every state, whether or not the cannabis was obtained legally. Officers may rely on field sobriety tests, drug recognition evaluations, and blood tests, and some states set specific THC limits or zero-tolerance rules. Consuming cannabis in a vehicle and carrying open or unsealed packages where the driver can reach them are commonly prohibited. If you have used cannabis, the safest choice is not to drive.

Crossing State Lines and Federal Law

Taking marijuana across state lines is illegal under federal law, even between two states where cannabis is legal, and it may also violate the law of the state you enter. Marijuana is also prohibited on federal land, in national parks, and at airports under TSA jurisdiction. In 2026 the federal government moved FDA-approved products and state-licensed medical marijuana to Schedule III, but adult-use marijuana remains a Schedule I substance, and rescheduling does not legalize interstate transport. Separate federal changes to the legal definition of hemp take effect in late 2026 and will restrict many intoxicating hemp-derived THC products.

Official Resource

Cannabis laws change often, and limits, penalties, and program rules can differ from what is summarized here. This page is general information, not legal advice. Before you rely on any detail, check the official state source below or consult a licensed attorney in Montana.