Are Automatic Knives Legal in Idaho?

The Short Answer

Yes — fully legal, and then some. Idaho is one of the most knife-friendly states in the country. Automatic knives, OTF knives, and switchblades are all legal to own, carry, buy, and sell with no restrictions on knife type or opening mechanism. Idaho has constitutional carry, statewide preemption (strengthened in July 2024 with HB 620), and no general blade-length limit. Knives with blades six inches or under aren't even classified as "deadly weapons" under Idaho law. If you're looking for a state where knife owners are left alone, Idaho is near the top of the list.

What Idaho Law Actually Says

The Definition (Idaho Code § 18-3302)

Idaho's concealed weapons statute defines "deadly weapon" in a way that specifically excludes most knives:

"Deadly weapon" means: (i) Any dirk, dirk knife, bowie knife, dagger or firearm; (ii) Any other weapon, device, instrument, material or substance that is designed and manufactured to be readily capable of causing death or serious bodily injury...

The term "deadly weapon" does not include: (i) Any knife, cleaver or other instrument that is intended by the person to be used in the processing, preparation or eating of food; (ii) Any knife with a blade six (6) inches or less...

What That Means in Plain English

Idaho draws a clear line at six inches:

• Blade 6 inches or under: Not a deadly weapon. Period. Carry however you want — open, concealed, no permit needed, virtually no restrictions beyond schools and courthouses.
• Blade over 6 inches: Classified as a "deadly weapon" but still legal to carry for most adults under Idaho's constitutional carry framework.
• Food-related knives: Excluded from "deadly weapon" classification regardless of blade length. A chef's knife, hunting knife used to dress game, or fillet knife is not a deadly weapon.

Idaho doesn't restrict any knife type. Automatic, OTF, switchblade, gravity, butterfly, assisted — the opening mechanism is legally irrelevant.

OTF Knives in Idaho

Fully legal without restriction. OTF knives of any blade length are legal to own and carry in Idaho. Most OTF knives have blades well under 6 inches, meaning they're not even classified as deadly weapons under Idaho law. You could carry one openly or concealed without a second thought.

Switchblades vs. Automatic Knives: What Idaho Considers Them

Idaho makes no legal distinction between these categories. There are no prohibited knife types in Idaho. The state doesn't mention switchblades, automatic knives, or any specific mechanism in its criminal code as restricted. The only thing that matters is blade length (for "deadly weapon" classification purposes) and who's carrying it.

Carrying an Automatic Knife in Idaho

Open Carry

Legal for all knife types and blade lengths. No restrictions. Idaho's constitution and § 18-3302(1) explicitly state that the provisions regulating weapons must be "strictly construed so as to give maximum scope to the rights retained by the people."

Concealed Carry

Idaho has constitutional carry under § 18-3302(4). Law-abiding adults can carry concealed weapons — including knives — without a permit. Here's how it works:

• Knives with blades 6 inches or under: Not deadly weapons. Essentially zero restrictions on concealed carry.
• Knives with blades over 6 inches: Still legal under constitutional carry for any person who is:
• 18 years of age or older
• A U.S. citizen or current member of the armed forces
• Not disqualified under § 18-3302(11)

Additional exemptions apply: a deadly weapon concealed in a motor vehicle is excluded from the concealed carry prohibition, as is carry on your own property or in your home.

Who Can't Carry Concealed

The disqualification list under § 18-3302(11) includes:

• Persons under 21 (for the license; constitutional carry applies at 18+)
• Convicted felons
• Fugitives from justice
• Unlawful drug users
• Persons adjudicated mentally ill
• Those discharged from the armed forces dishonorably
• Persons subject to domestic violence protection orders
• Anyone otherwise ineligible under Idaho or federal law

Where You Can't Carry (Restricted Locations)

• Schools (K-12): Under § 18-3302D, pocketknives with blades under 2.5 inches may be carried on school grounds and school buses. Knives with blades 2.5 inches or longer are prohibited on school property.
• Courthouses: Concealed deadly weapons (knives with blades over 6 inches) may not be carried in courthouses.
• Juvenile detention facilities and jails: Concealed deadly weapons prohibited.

Note the school rule — Idaho is one of the few states that explicitly allows small pocketknives on school property. That 2.5-inch threshold is unusually specific and practical.

Statewide Preemption

Yes — and it was strengthened in 2024. HB 620, effective July 1, 2024, added explicit preemption provisions prohibiting political subdivisions from enacting rules, ordinances, or taxes regarding knives. Any existing local knife ordinances are null and void.

This supplements the existing preemption in § 18-3302(18), which prohibits cities, counties, or political subdivisions from modifying the requirements of the concealed weapons statute. Idaho's state constitution (Article XII, § 2) also limits local regulations that conflict with general laws.

Bottom line: no city or county in Idaho can create its own knife restrictions.

What About Assisted Openers?

Legal without any restriction. Idaho doesn't regulate knives by opening mechanism. Since fully automatic knives are unrestricted, assisted openers are a complete non-issue.

Buying Automatic Knives in Idaho

Legal for adults. The only restriction on knife sales: under § 18-3302A, it is a misdemeanor to sell a dirk, dirk knife, bowie knife, or dagger to a minor. No purchase permits, waiting periods, or registration required.

Age Restrictions

• 18+: Constitutional carry of concealed deadly weapons (blades over 6 inches)
• Under 18: May not purchase dirks, dirk knives, bowie knives, or daggers
• School carry: Only pocketknives under 2.5 inches permitted on school grounds

Recent Law Changes

• July 1, 2024: HB 620 took effect, adding explicit statewide preemption for knife regulations. No political subdivision can enact rules, ordinances, or taxes regarding knives. Existing local knife laws are null and void.

Frequently Asked Questions

Can I carry an OTF knife in Idaho?

Yes. OTF knives are fully legal to own and carry — open or concealed — in Idaho. No permit required. Most OTF knives have blades under 6 inches and aren't even classified as deadly weapons.

Are switchblades illegal in Idaho?

No. Switchblades are fully legal in Idaho. The state has no prohibited knife types.

Is there a blade length limit for knives in Idaho?

No general blade length limit. Knives with blades over 6 inches are classified as "deadly weapons" but are still legal to carry under constitutional carry for qualifying adults. On school grounds, the limit is 2.5 inches.

Does Idaho preempt local knife laws?

Yes. Since July 1, 2024, Idaho law explicitly preempts all local knife regulations through HB 620. The existing § 18-3302(18) also prohibits modifications at the local level. No city or county can impose its own knife restrictions.

What knives are illegal in Idaho?

None. Idaho has no prohibited knife types. The only weapons restrictions relate to who can carry (felons, minors, etc.) and where (schools, courthouses), not what type of knife you own.

Legal Disclaimer

This article is for informational purposes only and does not constitute legal advice. Knife laws change — sometimes faster than websites update. Federal, state, and local laws may all apply to your situation, and local ordinances can be more restrictive than state law.

Before purchasing, carrying, or traveling with any automatic knife, OTF knife, or switchblade, verify current laws with official state and local sources. We are not attorneys, and we are not responsible for actions taken based on this information.

When in doubt, consult a licensed attorney in your jurisdiction.