You can carry a pistol in Yellowstone National Park if you are legally allowed to own a firearm and you follow the gun laws of the state you are standing in at that moment. The park sits across three states, with roughly 96 percent in Wyoming, 3 percent in Montana, and 1 percent in Idaho, and the rules shift when you cross an internal boundary. Firearms are banned inside every federal building in the park, and firing a weapon is illegal in almost every circumstance.
Why State Law Controls Inside the Park
Federal law prohibits the Secretary of the Interior from enforcing any regulation that would bar a legal gun owner from possessing a firearm in a national park, as long as possession complies with the law of the state where the park is located. That rule is codified at 54 U.S.C. § 104906 and mirrored in the National Park Service regulation at 36 C.F.R. § 2.4(a).1Office of the Law Revision Counsel. 54 USC 104906 – Protection of Right of Individuals To Bear Arms in Units of the National Park System2eCFR. 36 CFR 2.4 – Weapons, Traps and Nets
Because Yellowstone crosses three state lines, there is no single park-wide firearms policy. Three sets of rules overlap the same map, and you are responsible for knowing which one applies to the ground under your feet.3National Park Service. Gun Regulations in the Intermountain Region
Carry Rules for Each State in the Park
All three states allow open carry and permitless concealed carry. The age minimum is where visitors most often trip up.
Wyoming
Wyoming allows any U.S. resident who is at least 21 and legally permitted to possess a firearm to carry concealed without a permit. Residents and non-residents are treated the same, and open carry is also legal without a permit.4Wyoming Division of Criminal Investigation. CFP FAQ If you are 18, 19, or 20, you cannot legally carry concealed in the Wyoming portion of the park, which is nearly all of it.
Montana
Montana lets anyone 18 or older who can legally possess a firearm carry concealed without a permit, non-residents included, and open carry is also legal.5Montana State Legislature. Montana Code 45-3-111 – Openly Carrying Weapon – Display An 18-year-old carrying legally in the Montana section would need to unload and secure the pistol before crossing into Wyoming.
Idaho
Idaho allows any U.S. citizen or member of the armed forces who is at least 18 and not otherwise disqualified to carry concealed without a license. Open carry is also legal.6Idaho State Police. Concealed Weapons License Reciprocity The same age-boundary issue applies when moving into Wyoming.
Federal Buildings Are Off Limits
No matter which state you are in, taking a firearm into a federal building inside Yellowstone is a federal crime under 18 U.S.C. § 930. The statute reaches any building or portion of a building owned or leased by the federal government where federal employees regularly work, which in Yellowstone means visitor centers, ranger stations, and government offices.7Office of the Law Revision Counsel. 18 USC 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities
Under 18 U.S.C. § 930(h), you cannot be convicted unless signs were posted conspicuously at every public entrance or you had actual knowledge of the prohibition. The NPS confirms every restricted building in Yellowstone is signed at each public entrance.8National Park Service. Laws and Policies – Yellowstone National Park If you are carrying, secure the pistol in your vehicle before you go inside.
Firing a Pistol Is a Separate Offense
Carrying and discharging are treated as different acts under park law. Federal regulations prohibit using a weapon in a national park unit except in narrow circumstances that do not exist in Yellowstone, such as areas where hunting is specifically mandated by federal statute or designated target-practice facilities.2eCFR. 36 CFR 2.4 – Weapons, Traps and Nets The NPS states plainly that discharging a firearm in the park is illegal.9National Park Service. Visitor Compliance with Bear Spray and Hiking Group Size
Hunting is also prohibited. Under 36 C.F.R. § 2.2, taking wildlife in a national park unit is illegal unless a specific federal statute mandates otherwise, and no such statute exists for Yellowstone.10eCFR. 36 CFR 2.2 – Wildlife Protection
The one situation where firing a weapon might be defensible is genuine self-defense against an immediate threat of death or serious bodily injury. Even then, expect a full investigation. When a visitor shot a grizzly in Grand Teton, which operates under the same regulations, rangers and wildlife biologists reconstructed the encounter, the U.S. Fish and Wildlife Service was consulted because grizzlies are federally protected, and the U.S. Attorney’s Office reviewed the case before deciding on charges.11National Park Service. Investigation Results Made Public in 2012 Grizzly Bear Shooting Report any discharge immediately and cooperate.
Keeping a Pistol in Your Vehicle
Driving the park’s loop road can take you through all three states. Vehicle-carry follows the same state-law framework as on-foot carry, and Wyoming, Montana, and Idaho all allow a loaded handgun in a vehicle without a permit. A legal gun owner driving through Yellowstone can generally keep a loaded pistol accessible in the car. The firearm still has to come out before you enter any federal building.
Federal Safe Passage for Longer Trips
If Yellowstone is a leg of a longer drive and your pistol is legal at both your origin and destination but might not be legal in some state along the way, 18 U.S.C. § 926A provides a federal safe-passage right. To qualify, the firearm must be unloaded and stored so it is not readily accessible from the passenger compartment. If the vehicle has no separate trunk, the firearm and ammunition must go in a locked container other than the glove compartment or center console.12Office of the Law Revision Counsel. 18 USC 926A – Interstate Transportation of Firearms This covers transit only. Once you stop, camp, or hike, state law takes over again.
Penalties for Firearm Violations
The consequences here are federal. Carrying a pistol into a posted federal building without intent to commit another crime carries up to one year in prison, a fine, or both. If the government proves you brought the firearm in with intent to commit a crime, the maximum rises to five years.7Office of the Law Revision Counsel. 18 USC 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities
Illegally discharging a firearm or taking wildlife can bring charges under 36 C.F.R. § 2.4 and § 2.2, with fines and possible imprisonment.2eCFR. 36 CFR 2.4 – Weapons, Traps and Nets If the animal is a grizzly or another species protected under the Endangered Species Act, separate federal wildlife charges can stack on top of the park violation, and state charges are possible depending on the facts.