Montana cannabis laws for dispensary customers

Who regulates this

The Cannabis and Alcohol Regulation Division of the Montana Department of Revenue licenses growers, manufacturers, testing labs, and dispensaries. It also writes the rules those licensees follow. The statutes themselves live in Title 16, Chapter 12 of the Montana Code Annotated, with the tax provisions in Title 15, Chapter 64.

Everything below traces back to one of those two places. Where a number matters to a decision you are making, follow the citation and read it yourself, because the legislature revisits these rules every session.

Age and identification

Adult-use sales require a buyer 21 or older. The dispensary checks a valid, unexpired photo ID showing the date of birth. Expired IDs get refused, and so do photos of IDs.

The medical program starts at 18 for an applicant acting on their own behalf, with a card issued by the Department of Revenue. A minor may hold a card with guardian consent and two physician recommendations. A designated purchaser buying for a cardholder must be at least 21.

What you may possess

State law caps personal possession for adults 21 and over at 1 ounce of usable marijuana. Inside that ounce, no more than 8 grams may be in concentrated form, and no more than 800 milligrams of THC may be in edible products meant to be eaten or swallowed in solid form.

Read that as one shared ceiling, not three separate allowances. The Department of Revenue converts between formats at those same ratios when a mixed purchase counts against the limit.

Registered cardholders run against a different set of numbers: 1 ounce per day and 5 ounces per month, with a petition process for a higher monthly limit when a physician confirms the need.

Growing at home

Adults 21 and over may cultivate two mature plants and two seedlings at a private residence. Registered cardholders may cultivate four mature plants and four seedlings. In both cases the plants have to sit in a locked space and stay out of view from a public place.

Landlords may prohibit growing on a rental property, and a lease that says no is binding regardless of state law.

Where you may consume

Montana prohibits consuming cannabis in a public place and on trains, buses, and other public transportation. It prohibits smoking in a hotel or motel room unless the room was designated as a smoking room and rented to you.

That leaves private property, subject to whoever owns it. If you are visiting Great Falls, assume your hotel says no and check the property's policy before you book on that assumption.

Vehicles

Three separate rules apply here, and people tend to know only the first one.

Driving under the influence stays illegal. Montana sets a per se threshold of 5 nanograms per milliliter of delta-9 THC in blood.

Consuming inside a vehicle in operation is prohibited, and that applies to a passenger in the enclosed compartment, not only the driver.

Transport rules govern how the product travels. The Department of Revenue points customers to a locked glove compartment, a trunk, a truck bed, or another closed container that a driver or passenger does not normally occupy, with the product in its unopened original packaging. Violations of the transport rule carry a civil penalty of up to 100 dollars, and the state's guidance says such a violation does not go on a driver's record or affect motor vehicle insurance rates.

Crossing a state line with cannabis stays prohibited under federal law in every circumstance, including for cardholders.

Where sales are allowed

Montana lets counties decide. Counties that voted for the 2020 adult-use initiative allow licensed adult-use sales. Counties that voted against it do not, unless local voters change that. The Department of Revenue publishes the current county list, and it also shows which counties have adopted a local-option excise tax.

Product rules you will see on the shelf

State law caps flower at 35 percent total potential psychoactive THC and limits an individual flower package to 1 ounce. Edible and food product packages cap at 100 milligrams of THC, with a single serving capped at 5 milligrams as of July 1, 2026. Tincture and capsule packages cap at 800 milligrams, with individual capsules at 100 milligrams. Topicals cap at 6 percent THC concentration and 800 milligrams per package.

Every product in a licensed case has been through a licensed Montana testing lab, and the results are on the label.

At the counter

Bring the ID, bring the card if you have one, and expect the sale to stop at the possession limit even if you would rather it did not. The store's system reports to the state, and a budtender who works around a limit puts the license at risk.

Rules change with each legislative session, and 2026 already brought one change customers notice on the label. Check the Department of Revenue's cannabis pages for the current version before you rely on any number here.