Is THCA legal in Montana? Montana hemp, CBD and THC sales laws

The law in Montana

Montana's central hemp rule is a sales bar. Senate Bill 375, signed on May 5, 2025 and effective on approval, is now section 50-31-239 of the Montana Code Annotated: unless the FDA has authorized it as a food or drug, a hemp product containing total delta-9 THC may not be sold to a consumer in the state. The law defines a hemp product as one that contains postharvest hemp and is meant for consumption, smoking, vaping or another method of administration, and a consumer as a member of the public who takes the product and does not resell it.

The statute sets no amount: it reaches a product containing any total delta-9 THC. Hemp itself is defined in section 80-18-101 as Cannabis sativa L. and its derivatives, extracts, cannabinoids, isomers, acids and salts, with no more than 0.3 percent total delta-9 THC on a dry weight basis, and the definition leaves out synthetic cannabinoids.

1. May 22, 2023The Governor signs HB 948; the Department of Revenue says synthetic cannabinoid products became illegal that day.
2. April 7, 2025The Governor signs HB 49, which adds storage to the synthetic cannabinoid ban.
3. May 5, 2025The Governor signs SB 375, barring sales to consumers of hemp products containing total delta-9 THC, effective at once.
4. March 21, 2026Department of Revenue rules defining natural and synthetic cannabinoids, ARM 42.39.701 and 42.39.702, take effect.
5. December 11, 2026The federal limit of 0.4 mg total THC per container begins.

Two limits on the same products

Section 16-12-117, first enacted in 2023 as chapter 746 and amended in 2025, adds a second limit. Its third subsection says anyone selling hemp or hemp products may not exceed 0.5 mg of total delta-9 THC a serving or 2 mg a package, and its fourth subsection leaves out unadulterated hemp flower that has not been processed into extracts, infused products or concentrates.

In the notice adopting its synthetic cannabinoid rules in March 2026, the Department of Revenue wrote that natural cannabinoid products sourced from hemp can be sold in dispensaries if their total delta-9 THC stays within those per-serving and per-package limits. That notice does not mention section 50-31-239, and we found no rule, Attorney General opinion or appeals court ruling explaining how the 2023 caps and the 2025 sales bar fit together.

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THCA flower and delta-8

THCA counts in Montana because the hemp definition measures total delta-9 THC, and the Department of Revenue's rules describe heating as the step that turns delta-9 THCA into delta-9 THC. Flower over 0.3 percent total delta-9 THC is not hemp. For raw hemp flower within that line, section 16-12-117 does not apply, but section 50-31-239 bars selling a consumer a smokable hemp product that contains total delta-9 THC, and we found nothing that says how much flower that leaves on the market.

Synthetic cannabinoids are banned outright. The Department of Revenue says synthetic cannabinoid products became illegal on May 22, 2023, when the Governor signed House Bill 948. Section 16-12-117 now says no person may make, process, store or offer for sale a synthetic cannabinoid or a synthetic cannabinoid product; House Bill 49, signed on April 7, 2025, added storage to that list. The department's Cannabis Control Division names delta-8 THC, delta-10 THC, THC-O acetates, THCV, THCP, HHC, HHC-O acetate, HHCP and CBN as products to watch for.

Natural and synthetic, as the rules define them

The Department of Revenue's rules at ARM 42.39.701 and 42.39.702, effective March 21, 2026, draw the line by process. A natural cannabinoid is one present in the plant's biomass, including THC made by heating THCA without a chemical catalyst. A cannabinoid made by chemical synthesis, or by turning a natural acid into its neutral form with a chemical catalyst, is synthetic. When the department suspects a product holds synthetic delta-9 THC, the seller must show its natural origin by clear and convincing evidence.

Growing, age and topicals

The Montana Department of Agriculture licenses hemp growers, and its program page says a hemp license is required to grow hemp in Montana under a state plan approved by the USDA. We found no Montana statute that sets a minimum age for buying hemp or CBD products. Whether a CBD lotion or balm is a hemp product under section 50-31-239 depends on whether skin use counts as "another method of administration," and we found no rule or ruling that answers it.

Kratom, kava, amanita and spores

The 2025 Montana Code Annotated does not list kratom, mitragynine or 7-hydroxymitragynine in Schedule I under section 50-32-222, and we found no Montana statute that regulates kratom sales. Psilocybin and psilocyn are Schedule I. We found no Montana statute naming kava, amanita muscaria or its compounds, or mushroom spores.

The federal change on December 11

From December 11, 2026, the federal definition counts total THC including THCA and limits a finished hemp-derived cannabinoid product to 0.4 mg per container. Read the federal page and What's changing on December 11.