Montana Knife Laws: No Carry Rules Since 2017, Switchblades Since 2019, and the School Building Line

The Short Version

Montana's knife law was dismantled in two sessions. In 2017, House Bill 251 struck "dirk, dagger, sword" and "knife having a blade 4 inches long or longer" from the concealed weapons statute, 45-8-316, removed the phrase "or other deadly weapon," and rewrote the definition in 45-8-315 so that "concealed weapon" now means only "a firearm that is wholly or partially covered by the clothing or wearing apparel of the person carrying or bearing the weapon." In 2019, Chapter 119 repealed the switchblade statute, 45-8-331, and enacted 45-8-352, under which "local governments may not enact or enforce an ordinance, rule, or regulation that restricts or prohibits the ownership, use, possession, or sale of any type of knife that is not specifically prohibited by state law," with a single exception for property the local government owns or leases.

What is left is one place rule, 45-8-361, which makes it an offense to carry a knife with a blade of 4 inches or more, a sword or a straight razor inside a school building, and the ordinary law of assault. As AKTI puts it, "any knife may be carried openly or concealed." For a TEKTO customer every knife we make is a Montana knife, OTF automatics and the double-edged A7 Zastava included.

HB 251 (2017): Knives Leave the Concealed Weapons Law

Before 2017 Montana's concealed weapons statute read like most Western states': it was a crime to carry concealed "a dirk, dagger, pistol, revolver, slingshot, sword cane, billy, knuckles made of any metal or hard substance, knife having a blade 4 inches long or longer, razor, not including a safety razor, or other deadly weapon," with a permit available from the sheriff and exceptions for one's own premises, outside city limits, and while hunting or fishing. House Bill 251, signed in April 2017, deleted every non-firearm item from the list, removed the catch-all, retitled the section "Carrying concealed firearms," and narrowed the definition in 45-8-315 to firearms. The permit statute, 45-8-321, now concerns handguns, and since 2021 Montana does not require even that. Nothing in the current Code says anything about concealing a knife. A bowie knife under a coat in Billings is lawful, and a dagger in a boot in Butte is lawful, because the statute that used to say otherwise no longer mentions them.

Switchblades: Repealed in 2019

From 1957 to 2019 MCA 45-8-331 made it an offense to possess a switchblade, defined as a knife with a blade of 1.5 inches or more that opens automatically by a button, spring or other device in the handle. Chapter 119 of the 2019 Laws repealed it outright. The Code page now reads "Repealed. Sec. 2, Ch. 119, L. 2019." The same act created the preemption statute, so the repeal took effect statewide at once and no city may reinstate the ban locally. An OTF or side-opening automatic is lawful to make, sell, buy, own and carry in Montana with no condition, and the only statute that distinguishes knives by any feature is the school building rule, which measures blades rather than mechanisms.

Schools: 45-8-361 and the 4-Inch Line

Section 45-8-361 provides that "a person commits the offense of possession of a weapon in a school building if the person purposely and knowingly possesses, carries, or stores a weapon in a school building," and that "a parent or guardian of a minor commits the offense of allowing possession of a weapon in a school building if the parent or guardian purposely and knowingly permits the minor" to do so. "Weapon" means a firearm, "a knife with a blade 4 or more inches in length, a sword, a straight razor, a throwing star, nun-chucks, or brass or other metal knuckles," or "any other article or instrument possessed with the purpose to commit a criminal offense." "School building" means "all buildings owned or leased by a local school district that are used for instruction or for student activities." Three things follow. The rule is about buildings, not grounds, parking lots or buses. A folder under 4 inches is not a weapon under the statute, though every district's policy treats it as one. And a parent who hands a child a 4-inch knife to take to school commits the offense alongside the child. The penalty is a fine of up to $500, up to six months in the county jail, or both, with the knife subject to forfeiture.

Preemption: 45-8-352 and the Government-Property Exception

Section 45-8-352(1) bars local governments from restricting "the ownership, use, possession, or sale of any type of knife that is not specifically prohibited by state law," and since no knife is prohibited by state law, the bar is complete for ordinary carry. Subsection (2) carves out "a local government ordinance, rule, or regulation prohibiting the possession of a knife on property or in a building owned, leased, or possessed by the local government entity." A county may therefore bar knives from the courthouse, a city from city hall and the library, and a park district from its pools, by posted rule, and the remedy is removal or a municipal citation rather than a state charge. AKTI describes the statute as effective April 3, 2019. Billings, Missoula, Great Falls and Bozeman are under the state rules on this page everywhere but inside their own buildings.

Where You Cannot Carry

• School buildingsNo knife with a blade of 4 inches or more, no sword, no straight razor. Up to $500 and six months. The statute covers buildings, and school policy covers the rest of the campus and every knife.
  45-8-361
• Local government buildings and property that post a ruleCourthouses, city halls, libraries, pools and parks may bar knives under 45-8-352(2). Read the sign at the door.
  45-8-352(2)
• CourthousesBarred by court security and the county's own rule, with screening at the entrance. Leave it in the car.
  Court security
• Airports and federal propertyNo knives past the checkpoint at Bozeman Yellowstone, Billings Logan or Missoula under federal rules, and none in a federal building or courthouse under 18 U.S.C. 930. Glacier and Yellowstone follow federal park rules, which allow knives but not in federal buildings.
  TSA
• Tribal landThe Flathead, Crow, Northern Cheyenne, Fort Peck, Fort Belknap, Rocky Boy's and Blackfeet reservations set their own rules. Check before you carry.
  Tribal codes
• Private property and workplacesAn owner may bar knives and an employer may set a policy. The remedy is being asked to leave or being disciplined, and after that, trespass.
  Trespass

Minors and Threats

Montana sets no minimum age to buy, own or carry a knife and has no youth-specific knife statute outside the school building rule, where the parent who permits the knife is the one the statute names. On the other end, 45-5-213 makes assault with a weapon, purposely or knowingly causing bodily injury or reasonable apprehension of serious bodily injury "with a weapon," a felony punishable by up to twenty years, and a knife used or brandished that way is a weapon whatever its length. The knife that is lawful everywhere in Montana stops being lawful the moment it is part of a threat.

Penalties

Montana has no state misdemeanor for carrying a knife. The school statute is the only knife-specific offense in the Code.

What the Internet Gets Wrong

Three things. First, that Montana bans concealed carry of knives with blades of 4 inches or more. It did, until April 2017. The 4-inch figure now lives only in the school building statute. Second, that switchblades are illegal. The ban was repealed in 2019. Third, that Montana has no local knife rules at all. It has none for ordinary carry, and a specific exception for a local government's own buildings and property, which is why the courthouse and the library can still turn you away. The rule that catches people is the parent at the school: a 4-inch folder in a pocket at a parent-teacher conference is the one knife offense left in the state.

TEKTO Knives for Montana

Every TEKTO knife is a Montana knife. The A5 Spry in any blade style and the A7 Zastava with its double-edged spear point are lawful in a pocket, lawful on a belt and lawful in the truck. The A3 Delta is a 3.60-inch side-opening automatic with a button lock and safety. The X1 Atlas fixed blade in MagnaCut, at 3.30 inches, is the knife for the Bob, the Beartooths and the Missouri Breaks, and it is under the school building line, which matters only at the door of the gym.