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William E. Weiss
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Judge holding knife in court

This article about knife laws is for informational purposes. It points out specific laws for the jurisdiction I mention in the article. It also lets you know you may have to check on a particular jurisdiction’s (i.e. city, county, state) statutes, ordinances and rules to see if what you are carrying is legal. You can find these ordinances on the public entity’s website. I have received hundreds of inquiries and cannot answer them all so I encourage you to take a look on the relevant website.

Remember that carrying any weapon, even one that’s legal, can cause you a lot of grief with law enforcement.  Cops routinely write tickets and make arrests for things they incorrectly think are illegal, or full well know not to be illegal. Beating a rap in court is great, but better is never being there in the first place.

In California, the state knife laws are the baseline law, and cities can make more restrictive knife laws on top of the state laws.  See Yuen v. Municipal Court, 52 Cal.App.3d 351 (1975) or People v. Gerardo, 174 Cal.App.3d Supp. 1 (1985).  Since we’ve addressed the state laws in other entries in this series, this synopsis places the South Alameda County laws first, and then below these outlines the state laws that form the baseline rules. 


Compared with much of the Bay Area, Alameda County takes a relatively hands-off approach to regulating knives. The County has knife laws that are stricter than the state’s baseline, but only slightly so, and the focus is strictly on minors, ie. people under the age of 18.  Alameda County’s jurisdiction covers all unincorporated areas, which includes the following municipalities: Albrae, Altamont, Asco, Ashland, Baumberg, Brightside, Brookshire, Carpenter, Castro Valley, Cherryland, Dougherty, Dresser, East Pleasanton, Fairview, Farwell, Hall Station, Halvern, Kilkare Woods, Komandorski Village, Lorenzo Station, Mattos, Mendenhall Springs, Midway, Mountain House, Mowry Landing, Radum, San Lorenzo, San Ramon Village, Scotts Corner, Sunol, Sorenson and Verona. 

In the unincorporated territory of Alameda County, it is illegal to sell, give, loan, or in any way furnish a “dangerous weapon” to a minor, or to cause or permit a “dangerous weapon” to be sold, given, loaned, or in any way furnished to a minor, or to allow any minor to use or possess a “dangerous weapon,” or for any minor to use or possess a “dangerous weapon.” See Alameda County Code of Ordinances § 9-12.060.

Blades that the County of Alameda considers to be “dangerous weapons” include: any knife with a blade that’s three inches or longer; any snap-blade or spring-blade knife regardless of the length of the blade, any ice pick or similar stabbing tool; any cutting, stabbing or bludgeoning weapon or device capable of inflicting grievous bodily harm; any dirk or dagger or bludgeon or blackjack; and any straight edge razor or any razor blade fitted to a handle. See § 9-12.050.

Like most California jurisdictions, the County of Alameda makes an exception to their additional restrictions on “dangerous weapons” when these are possessed, used or controlled by a minor for purposes of lawful employment or lawful recreation.  See § 9-12.070.  Since all of Alameda County’s restrictions are related to minors’ use or possession of weapons, and adults’ unlawful enabling of that use, it logically also has an exemption for minors’ permissive use. So, in unincorporated Alameda County, the selling, giving, loaning, or furnishing a dangerous weapon to any minor is permitted with the written consent of the minor’s parent or guardian, and a minor may use, possess or control a dangerous weapon with the consent of the parent or guardian under the direct supervision and control of some adult person.  See § 9-12.070. 

However, if a minor possesses or controls a dangerous weapon while engaging in a fight or participating in any rough or disorderly conduct, then the permission exception does not apply, and he can be charged for unlawful possession in addition to the disorderly conduct rap.  See § 9-12.080

Violation of any of the above laws is a misdemeanor carrying a penalty of up to 6 months in the clink, a $1,000 fine, or both the time and fine.  See Cal. Pen. Code § 19.


Fremont bans the possession, control, sale, use, gift, loan or furnishing to anyone and by anyone of a “dangerous weapon.” See Fremont Municipal Code § 9-15.050.

In Fremont, a “dangerous weapon” is any knife with a blade that’s two inches or longer (whether carried openly or concealed), all switch-blades and snap-blades regardless of length, any icepick or stabbing tool, any straight-edged razor or razor blade fitted to a handle, and any cutting, stabbing or bludgeoning weapon or device capable of inflicting bodily harm.  See FMC § 9-15.060

Fremont, like almost all California jurisdictions, also has an exception to dangerous weapon possession for purposes of lawful employment or recreation, and specifically exempts hunting knives carried in a sheath outside of the clothing while such person is engaged in lawful sport in which the use of such a knife is appropriate or going to or from such lawful sport, along with the possession or use of otherwise prohibited knives used in connection with bona fide organized and supervised youth activities, and the possession or use of any such instrument in lawful domestic or commercial pursuits. See § 9-15.060. 

Fremont also carves out an exception for use of any of the above weapons to defend life or property, and to lawfully protect life, property, or crops from destruction or damage by any predatory or destructive bird or animal. See § 9-15.090.  That said, even in the self-defense situation, you’d still be on the hook for state law violations if there were any. For instance, if you use a 3″ switch-blade to stick someone who had crept into your home, according to this section, you’d not face city charges for use of the prohibited blade, but that doesn’t mean you couldn’t face state possession charges under California Penal Code sections 17235 and 21510.

Violation of any of the above ordinances (aside from the state law ones) is a misdemeanor with a penalty of up to six months in the slammer, a $1,000 fine, or both.  See § 1-15.020(a) & Cal. Pen. Code § 19.


Pleasanton has no additional knife laws, so only the default state laws apply. 


In Livermore, it is unlawful for any person to wear or carry concealed about his person any dirk (see state laws for definition), Bowie knife, metal knuckles, or other dangerous or deadly weapon, without first obtaining a written permit to do so from the Chief of Police. See Livermore Municipal Code § 9-76.010.  This means that to carry such weapons, you must obtain a permit from the city, not the Chief directly.  The term “dangerous or deadly weapon” is not defined in the city code, so it will default to the state definition, which is “any weapon, instrument, or object that is capable of being used to inflict great bodily injury or death,” including pretty much every knife ever made. See People v. James, 88 Cal.App.3d 150 (1978). 


The only knife ordinance that Union City has beyond the state laws is Union City Municipal Code chapter 12, section 28.270, under which any hatchet, axe, machete, brush knife or any other cutting device capable of harming a tree or plant (other than a pocket knife) is prohibited in public parks, plazas, promenades, playgrounds, and recreation areas without permission of the City’s Leisure Services Department. See § 12-28.270(A). While this sounds like they’re trying to prohibit vandals from wrecking the park, make no mistake that this is a knife control law. Utensils used in the preparation of meals, however, are excepted.  See § 12-28.270(B).     


The only additional knife law in Newark follows Union City’s very closely, declaring it unlawful for any person to carry in any public park or recreation area any hatchet, axe, machete, brush knife or any other device other than pocket knife, capable of cutting, defacing or mutilating trees or shrubs, without the permission of duly authorized City representatives. See Newark Municipal Code § 12-16.260.  In this case, it’s the same as Union City: while this sounds like they’re trying to prohibit vandals from wrecking the park, make no mistake that this is a knife control law, and that you should mind what you bring into any park space.  


Here are the baseline knife laws in California.    

Concealed Knives, Dirks, and Daggers – Penal Codes § 12020, § 20200 & § 21310

In California, folded pocket knives are legal, but it is illegal for any person to concealed carry any knife legally described as a “dirk” or “dagger” — the legal terms for any fixed-blade knife or stabbing weapon.  See § 12020(4). Even a locked pocket knife can count, so can a screwdriver in some cases. See § 16470.  BUT carrying a “dirk” or “dagger” in an openly-worn sheath hanging on your hip is not concealment within the meaning of the statute.  See § 12020(25)(d) and § 20200.   

Switchblades  – Penal Codes § 17235 & 21510

Switchblades and other spring-loaded knives are illegal in California if their blade is 2″ or longer. A switchblade is a knife with “the appearance of a pocketknife and includes a spring-blade knife, snap-blade knife, gravity knife, or any other similar type knife, the blade or blades of which are two or more inches in length and which can be released automatically by a flick of a button, pressure on the handle, flip of the wrist or other mechanical device, or is released by the weight of the blade or by any type of mechanism whatsoever.” See § 17235.  The statute expressly excludes pocket knives that can be opened with one hand by pushing the blade open with one’s thumb, as long as the knife “has a detent or other mechanism that provides resistance that must be overcome in opening the blade, or that biases the blade back toward its closed position.” See § 17235.  Basically, your regular pocket knife is legal, and switchblades are legal if they’re under 2″.   

The law is zero tolerance on these, and they’ll bang you with a misdemeanor charge if you: (a) possess the knife in the passenger’s or driver’s area of any motor vehicle in any public place or place open to the public; (b) carry the knife upon the person; (c) sell, offer for sale, expose for sale, loan, transfer, or gives the knife to any other person. See § 21510.  The Court of Appeals held that possession of a switchblade in a person’s pocket, boot, etc., is unlawful, even if even if in one’s own home.  See People v. S.C. (2009).  Modifying a pocket knife into a switchblade-like knife makes it a switchblade.  See People v. Angel R. (2008). 

Cane Swords and other Disguised Blades – Penal Codes § 16590 

Generally, any knife or blade that is disguised so as to not look like a weapon is also illegal in California. See § 16590.  This includes, cane swords (§ 16340), belt-buckle knives (§ 16260), lipstick case knives (§ 16830), air gauge knives (§ 16140), writing pen knives (§ 17359), so-called ballistic knives (§ 16220), a staff or crutch (§ 17260), etc.  Blades that are undetectable to metal detectors (e.g., ceramic blades) are also illegal. See § 20810 and § 17290.  Remember, just because your blade isn’t explicitly described under the law, doesn’t mean the cops can’t find some way to write you up under the closest description.  I once had a client wearing rings the police magically made into “metal knuckles” under PC § 21810 because he was wearing a cut. They also used the cut to add a gang enhancement to the “weapon” of rings, sorry, “metal knuckles.”       

Possession of Knives on School Grounds – Penal Code § 626.10

It is illegal for any person to bring or possess “any dirk, dagger, ice pick, knife having a blade longer than 2 1/2 inches, folding knife with a blade that locks into place, [or] razor with an unguarded blade . . . upon the grounds of, or within, any public or private school providing instruction in kindergarten or any of grades 1 to 12 . . .”  See § 626.10(a)(1). Subsection (b) of the statute provides that it is illegal for any person to possess “any dirk, dagger, ice pick, or knife having a fixed blade longer than 2 1/2 inches upon the grounds of, or within, any [college or university].”

Possessing a Knife in a Government Building – Penal Code § 171b

Legal blades 4″ or longer that are fixed or capable of being fixed are illegal within any state or local public building or at any meeting required to be open to the public. See § 171b(A)(3). Here, a “state or local public building” is a building that is owned or leased by the state or local government, with state or local public employees working on a regular basis. See § 171b(C)(1). 

Brandishing Knives – Penal Code § 417

In California, it is illegal to brandish any deadly weapon, knives included.  See § 20200-21590 broadly. The law states that it is unlawful for any person to “draw or exhibit any deadly weapon . . . in a rude, angry, or threatening manner, or . . . to unlawfully use a deadly weapon.”  See § 417(A)(1).  This does not include use of such a weapon in self defense. See § 417(A)(2). Watch out, there is a mandatory minimum on this one of thirty days, in addition to anything else they nail you for.  See § 417(A)(1).

So that’s where we stand!

Bill Weiss has long experience in personal injury and civil rights cases on behalf of the motorcycle community. He is one of the only attorneys in California that represents bikers in civil rights cases against law enforcement. He has recovered millions of dollars on behalf of his clients who have been injured in motorcycle collisions and other personal injury cases, as well as civil rights cases.   

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