Montana Knife Laws: What You Need to Know

The Essentials

Legal to Carry Concealed or Openly

  • Any kind of knife; last of prohibitions removed from legislation as of April 2019.

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Montana Knife Law Overview

Montana is one of the friendliest states for knife carry since ongoing revisions of their knife law began in 2017. As of April 2019, there are no restrictions on length, type, action, or anything else to hamper your choice of what to carry and where you can carry it, barring a length restriction on knives in or on school property.

Where previously there were a few restrictions on the carry of ever-mysterious dirks, daggers and other knives, including automatic “switchblades”, today there are no such regulations.

Repeal, baby, repeal! Montanans today enjoy some of the broadest knife freedoms in the nation.

This is all backed up by excellent statewide preemption statutes that prohibit any municipality from infringing on your rights, at least in excess of what the state proscribes and they don’t proscribe much! Let’s get to the good news and look at the relevant Montana State statutes in the text below!

Relevant Montana State Statutes Covering Use and Ownership of Knives

  • MCA 45-2-101
  • MCA 45-8-315
  • MCA 45-8-352
  • MCA 45-8-361

We begin with definitions, found in MCA 45-2-101. As with all statutes, the legal definitions of otherwise obvious words may result in significant deviations from baseline meanings that can manifest in sweepingly different interpretations of the law.

It is always worth the time to look up and understand the meanings of all words as they are used in the statutes! Fortunately, Montana is a bastion of sanity in a wasteland of legal lunacy:

45-2-101. General definitions. Unless otherwise specified in the statute, all words must be taken in the objective standard rather than in the subjective, and unless a different meaning plainly is required, the following definitions apply in this title:

(35) ”Knowingly”–a person acts knowingly with respect to conduct or to a circumstance described by a statute defining an offense when the person is aware of the person’s own conduct or that the circumstance exists.

A person acts knowingly with respect to the result of conduct described by a statute defining an offense when the person is aware that it is highly probable that the result will be caused by the person’s conduct.

When knowledge of the existence of a particular fact is an element of an offense, knowledge is established if a person is aware of a high probability of its existence. Equivalent terms, such as “knowing” or “with knowledge”, have the same meaning.

(43) ”Negligently”–a person acts negligently with respect to a result or to a circumstance described by a statute defining an offense when the person consciously disregards a risk that the result will occur or that the circumstance exists or when the person disregards a risk of which the person should be aware that the result will occur or that the circumstance exists.

The risk must be of a nature and degree that to disregard it involves a gross deviation from the standard of conduct that a reasonable person would observe in the actor’s situation.

“Gross deviation” means a deviation that is considerably greater than lack of ordinary care. Relevant terms, such as “negligent” and “with negligence”, have the same meaning.

(59) ”Possession” is the knowing control of anything for a sufficient time to be able to terminate control.

(66) (a) ”Serious bodily injury” means bodily injury that:

(i) creates a substantial risk of death;

(ii) causes serious permanent disfigurement or protracted loss or impairment of the function or process of a bodily member or organ; or

(iii) at the time of injury, can reasonably be expected to result in serious permanent disfigurement or protracted loss or impairment of the function or process of a bodily member or organ.

(b) The term includes serious mental illness or impairment.

(79) ”Weapon” means an instrument, article, or substance that, regardless of its primary function, is readily capable of being used to produce death or serious bodily injury.

The definitions in Montana are plain, easily understood and were written to be so, with the in-law instruction that they should always be interpreted objectively.

Above, “knowingly” and “negligently” are two concepts one should always be familiar anytime use of force or weapons, especially ones considered “lethal” weapons are in play. Both terms pop up regularly in such legislation and discussions.

“Serious bodily injury” is quantified according to the usual standard, and includes a significant risk of death, disfigurement or a crippling injury.

Interestingly, Montana also includes mental illness and impairment as under the province of serious bodily injury, making mental distress or PTSD qualifiers, if I were to wager.

Most importantly, “weapon” is defined very closely to its dictionary definition, and means any tool that is capable of inflicting death or serious bodily injury on a person. This includes all purpose made weapons, of course, but would, in Montana, even include primordial tools and weapons like rocks or sharpened sticks if they were used accordingly with intent.

Montana goes further to define weapons in the context of concealed weapons, this definition being found in 45-8-315 and it is just as short and simple as the previous one:

45-8-315. Definition.

“Concealed weapon” means a firearm that is wholly or partially covered by the clothing or wearing apparel of the person carrying or bearing the weapon.

Here we see that, in the context of the statutes, “concealed weapon” refers only to firearms, nothing else. Interesting.

Montana also makes this broadly interpretable based on the standard of concealment being quite low; “partially covered by clothing” could mean as little as a part of your shirt draping over the hammer of your pistol.

That, though, is a conversation for another article- we are here for knives today, not guns!

In essence there is no law or prohibition whatsoever against the carry of knives, of any kind.

No-Go Zones

The law is fairly clear on areas in which you are barred from carrying a concealed weapon, with a few question marks. Schools and federal buildings certainly, and perhaps state and local governments, financial institutions and any place where alcohol is sold to be consumed on the premises.

The reason for the discrepancy? The statute on schools plainly states that knives over a certain length are forbidden, while federal buildings operate under federal law.

The others specifically forbid “concealed weapons” which you will no doubt recall from the definitions in the preceding statutes specifically refers to guns, not knives.

At any rate, here are the specific passages relating to weapons in schools, 45-8-361:

45-8-361. Possession or allowing possession of weapon in school building — exceptions — penalties — seizure and forfeiture or return authorized — definitions.

(1) 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.

(2) 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 possess, carry, or store a weapon in a school building.

(3) (a) Subsection (1) does not apply to law enforcement personnel.

(b) The trustees of a district may grant persons and entities advance permission to possess, carry, or store a weapon in a school building.

(4) (a) A person convicted under this section shall be fined an amount not to exceed $500, imprisoned in the county jail for a term not to exceed 6 months, or both. The court shall consider alternatives to incarceration that are available in the community.

(b) (i) A weapon in violation of this section may be seized and, upon conviction of the person possessing or permitting possession of the weapon, may be forfeited to the state or returned to the lawful owner.

(ii) If a weapon seized under the provisions of this section is subsequently determined to have been stolen or otherwise taken from the owner’s possession without permission, the weapon must be returned to the lawful owner.

(5) As used in this section:

(a) ”school building” means all buildings owned or leased by a local school district that are used for instruction or for student activities. The term does not include a home school provided for in 20-5-109.

(b) ”weapon” means any type of 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. The term also includes any other article or instrument possessed with the purpose to commit a criminal offense.

Here weapon includes knives that are 4 or more inches in length, swords and other bladed instruments. Of interest to some parents, perhaps, is 3(b), which states that trustees of a school district can grant permission to carry a weapon the school premises.

It is not unthinkable that one well-known and trusty sort could be entrusted (in writing, of course) to carry by the school authorities.

Note here also that the penalty for violating this section is quite mild by the typical standard of punishment; a maximum of a $500 fine and, potentially, up to 6 months in the county clink, though the passage instructs the court to seek alternatives to incarceration.

Interesting. Many states the same offense, “innocently” violated or not will get you slapped with a felony and a major fine, not to mention a lengthy stay at the hotel Graybar.

My advice is this, whatever the law says: while I want to carry everywhere and anywhere I can, you should always use extreme discretion when and if you choose to carry any weapon, knives included, on government property at the local or state level.

It would be too easy a thing for a minor scare or kerfuffle to snowball into some kind of heat you don’t want a charge you can ill afford.

My personal policy is to abstain from carrying any weapon worse than pepper spray where guns are themselves restricted on government property.

Carrying into “restricted” areas like concerts, sporting events, social gatherings and so on is one thing, even if you are caught. Getting caught doing so or accused of doing so with nefarious purpose on government property is another thing entirely.


A solid and resounding “yes!” Montana’s state laws (rather lack thereof) governing knives in conjunction with staunch preemption laws means you have a ticket to ride as far as the carry of knives is concerned. Section 45-8-352 reads:

45-8-352. Restriction on local government regulation of knives.

(1) Except as provided in subsection (2), 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.

(2) Subsection (1) does not apply to 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.

So while local governments can regulate the carry and possession of knives on governments property, that is as their rules can go; the rest of the local area remains free of undue and heavy-handed laws!

Bottom Line

Montana is one of the friendliest and most permissive states for knife owners, and has hardly any regulations to speak of governing their possession or carry anywhere since a rolling revision of knife and weapons law began in the year 2017.

Montana’s strong statewide preemption also means you will never have to fear running into restrictive local ordinances so long as you keep schools, courts and other government buildings in mind.

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