Montana Knife Laws

October 3, 2019
Amerian flag with knife

Montana knife laws are among the top tier of friendliest knife laws in the country.

What the Law States

Montana amended its knife laws, effective October 1, 2017, by removing from the definition of concealed weapon “a knife with a blade 4 inches or more in length that is wholly or partially covered by the closing or wearing apparel of the person carrying or bearing the weapon.”  Under the new law, only firearms are within the definition of “concealed weapon.” § 45-8-315, MCA.   Moreover, ambiguous knife definitions, such as dirk, dagger, and sword cane, were removed from the list of prohibited items to carry concealed by the amendment, effective October 1, 2017.


Annotated 2017

Montana amended its knife laws, effective October 1, 2017, by removing from the definition of concealed weapon “a knife with a blade 4 inches or more in length that is wholly or partially covered by the closing or wearing apparel of the person carrying or bearing the weapon.”  Now, with newly-enacted laws, only firearms are within the definition of “concealed weapon.” § 45-8-315, MCA.  

Annotated 2019

As of April 3, 2019, Montana enacted knife legislation to remove the limitation on carrying and use of an automatic knife with a blade of less than one and one half (1-1/2″) inches. Concealment is no longer an issue in Montana and you may either conceal or not.

What is Legal to Own

It is legal to own any knife

What is Illegal to Own


Limits on Carry

None … except …. according to § 45-8-361, MCA it is not legal to bring a knife or blade of 4 inches or longer to schools.

Definition of Deadly Weapon

Montana code § 45-2-101 defines “weapon” any instrument that is readily capable of being used to produce death or serious bodily injury, regardless of its primary function.

Definition of Concealed Carry

Concealed carry of knives is no longer a problem.

Exceptions to the Concealed Carry Law

The law in Montana exempts several classes of people from the concealed carry law, and allows concealed carry of weapons for certain government employees and members of the National Guard. The law also exempts those who are outside the boundaries of a city or town and are participating in lawful recreational activities where it is common to carry a weapon, such as hunting, fishing, trapping, framing, ranching, or hiking. A person is also exempt from the concealed carry law when he or she is carrying the weapon in his or her own home or place of business, or has a permit to carry a concealed weapon.

Conclusion on Montana Knife Laws

Montana allows residents to possess and open carry any type of knife, including a switchblade as of early 2019 after new legislation passed.

Knives or blades of 4 inches or longer should be kept away from any schools to avoid violating the law.


Mont. Code Chapter 8, Part 3

About The Author

21 comments on “Montana Knife Laws”

  1. 45-8-317. Exceptions. (1) Section 45-8-316 does not apply to:
    (a) any peace officer of the state of Montana or of another state who has the power to make arrests;
    (b) any officer of the United States government authorized to carry a concealed weapon;
    (c) a person in actual service as a member of the national guard;
    (d) a person summoned to the aid of any of the persons named in subsections (1)(a) through (1)(c);
    (e) a civil officer or the officer’s deputy engaged in the discharge of official business;
    (f) a probation and parole officer authorized to carry a firearm under 46-23-1002;
    (g) a person issued a permit under 45-8-321 or a person with a permit recognized under 45-8-329;
    (h) an agent of the department of justice or a criminal investigator in a county attorney’s office;
    (i) a person who is outside the official boundaries of a city or town or the confines of a logging, lumbering, mining, or railroad camp or who is lawfully engaged in hunting, fishing, trapping, camping, hiking, backpacking, farming, ranching, or other outdoor activity in which weapons are often carried for recreation or protection;
    (j) the carrying of arms on one’s own premises or at one’s home or place of business; or
    (k) the carrying of a concealed weapon in the state capitol by a legislative security officer who has been issued a permit under 45-8-321 or with a permit recognized under 45-8-329.
    (2) With regard to a person issued a permit under 45-8-321, the provisions of 45-8-328 do not apply to this section.

      1. As long as it is EASILY able to be noticed by the public (which shouldn’t be hard with a sword) you could walk around with a greatsword if you wanted. Have fun.

  2. I’m confused as to brass knuckles. If they’re considered a deadly weapon, are they legal to openly carry? Or even to own?

  3. So….swordcanes are legal if the blade itself doesnt exceed 4 inches AND you have your concealed weapons permit?

  4. Why are switchblades illegal to carry or even own like really I could pull a spring assisted knife just as fast as a automatic knife and it illegal to conceal carry any knife with a blade of 4″ or longer? What? Not everyone owns a sheath I just think we should consider those two laws for they are kinda rediculous please help me I want to find out why we have these laws

  5. does a sheath count a clothing? say I’m wearing a knife on my belt that’s over four inches, you can see the bottom of the sheath coming from under my sweatshirt but u can’t actually see the knife. btw I’m 13 turning 14 in two weeks so I am a minor

    1. yes, a sheath is a concealer. if you want to carry it around public you will need a permit. But since your blade length is over 4in it doesn’t change the fact that it’s already illegal to carry to begin with. Spring-assisted knives, however, can be legal to carry because it is NOT a fixed blade and DOES NOT require a push of a button. If your planning to carry a knife around public, I’d say get a spring-assisted one, Karambit is my favorite to carry. Btw, if you’re seen pulling out any type of knife looking thing in public, you can get one hell of a problem, so don’t think itll be cool to show off your friends in public that ur carrying a weapon. (you’ll think it’s cool, but you’ll know it isnt in several year. aka, GL getting a good or any kind of job).

    2. Knifes are illegal for minors to carry in total no matter what it is its illegal but yes if you have a sheath holding a let’s say a combat knife it is legal to have on ur belt as long as ur 18 or older

  6. Can private businesses restrict knives in anyway? I was recently barred entry from a bar because they were frisking anyone going in and asked if I had any pocket knives. I told them I had two (one a part of my leatherman, the other a stand-alone 2.5″ blade). They said they wouldn’t allow those in the building. “Just put them in your car,” the security guy said.

    “I don’t have a car; I walked here.”

    “Well, you could just hide it outside somewhere and pick it up when you leave.”

    Yeah…no. I was frustrated since I knew these knives were legal to carry, but I wasn’t sure if private businesses were allowed to bar them.

  7. Is it illegal to carry a trench knife in Montana? I ordered a folding EMS trench knife for self defense and no where except Texas has laws for trench knives.

  8. I’m confused, are switchblades
    legal in MT
    are they ONLY legal if they’re less than 2″ in length?

  9. So I own a couple different Kukri blades one of them is in between 13-17 inches overall the other being 9” length. If I wanted to could I carry that anywhere aside from government buildings?

    Also knives like a Karambit, I’m guessing that would be considered a deadly weapon?

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