Marijuana in Yellowstone and Grand Teton National Park.

Where marijuana citations come from

The gateway towns on the Montana side of Yellowstone sell cannabis over the counter, and a great many visitors buy there on the way in without a thought about jurisdiction. From the south, Colorado product travels north through Jackson and into Grand Teton in the same glove box it left the dispensary in. Almost every marijuana notice in the parks starts as something else: a speeding stop on the highway through Grand Teton, a taillight on the Grand Loop, a wildlife jam that a ranger is clearing. The federal courts that cover Wyoming have long treated the smell of marijuana coming from a vehicle as enough to search it, and the ranger's report will describe the odor, the question, and the answer in that order. What was said in the first two minutes of the stop tends to decide whether the case is about possession or about something more.

The other source is a ranger on foot at dusk: a joint at a campsite, a pipe at a trailhead, a group at a lake shore. These are the cases that add a second charge, because a visitor who is visibly impaired near a river, a cliff, or a thermal feature can be cited for presence under the influence as well as possession, and a shared joint can be written as delivery for the person who passed it. The same section separately prohibits delivery, defined as any actual, attempted, or constructive transfer (§ 2.35(b)(1)), and being present in the park under the influence of alcohol or a controlled substance to a degree that may endanger oneself, another person, or park resources (§ 2.35(c)). Each is a petty offense with the same six-month, $5,000 ceiling as the rest of the regulations.

Edibles, vapes, and things labeled hemp

Federal law does not distinguish a gummy from a bud; a THC edible or a vape cartridge made from marijuana is marijuana, and a pen with residue is a possession case. Hemp-derived products occupy a shrinking legal space: hemp within the federal THC limit has been outside the controlled-substances act since 2018, but a law signed in November 2025 narrows the definition to total THC with a per-container cap and takes effect in November 2026, after which most of the intoxicating hemp gummies and vapes sold at gas stations count as marijuana. None of that is visible on the roadside. A ranger sees a product, seizes it, and a laboratory report weeks later decides what the case is.

Medical cards after the 2026 rescheduling

For years the answer to "I have a medical card" was short: a state card is not a federal prescription, marijuana could not be prescribed under federal law at all, and the park regulation did not care what the state had authorized. On April 28, 2026, the Drug Enforcement Administration changed part of that. Its rule moved marijuana in FDA-approved products and marijuana "subject to a state medical marijuana license" from Schedule I to Schedule III, while leaving every other form of marijuana, including everything sold for adult use, in Schedule I. The same rule treats a state medical certification, properly dated and signed, as sufficient for a federally registered dispensary to dispense.

What the rule does not do is mention patients, possession, or federal land. Whether product that left a licensed medical dispensary is still "subject to" that license in a patient's backpack, and whether a state certification is a "valid prescription or order from a practitioner" within the park regulation's exception, are questions the rule leaves open and the court at Mammoth has not, to my knowledge, answered. A broader proceeding on whether all marijuana belongs in Schedule III finished its hearings in July 2026 and awaits a decision. The practical position for a patient cited in the park is therefore new and unsettled, which is the opposite of a reason to pay the notice. Keep the certification and the receipt, decline to discuss either with the ranger, and bring both to the first conversation with counsel.

Prescription medication, and everything that is not marijuana

Stimulants, sedatives, sleep aids, and opioid pain medication are all controlled substances, and all of them are carried through the parks every day by people who are entitled to them. The regulation's exception covers medication obtained from a practitioner or on a valid prescription, and it does not require the original bottle. A citation for prescribed medication is usually a paperwork problem that the pharmacy's records solve. The exceptions are the ones you would expect: someone else's prescription, a spouse's medication packed by mistake, or a quantity that no prescription accounts for.

Psilocybin, MDMA, cocaine, LSD, and ketamine without a prescription are all "other substances" on the court's schedule, which means no pay-by-mail option and a required appearance before the magistrate judge. Quantity and packaging decide whether the government treats the case as personal possession under the regulation or reaches for the federal possession statute, which carries up to a year, and a search that turns up scales or multiple bags is a different case from a search that turns up a bag of mushrooms at a trailhead. Nothing on this page should be taken as a description of how those cases end; that depends on facts I have not heard yet.

The firearms form

The federal firearms purchase form asks whether the buyer is an unlawful user of marijuana and warns that state legalization does not change the answer; the Supreme Court held in June 2026 that a marijuana user cannot be prosecuted for possessing a gun on that ground alone (United States v. Hemani), but a false answer on the form remains its own federal offense. As in every park case, the object is to end the matter with a fine and without a conviction that has to be disclosed. Whether that is available in a possession case depends on the amount, the facts of the stop, your record, and the prosecutor's view of all three; it is never available to the person who paid the notice the week it arrived.