Here is a portion of the IL statute.
§ 24-1. Unlawful Use of Weapons.
(a) A person commits the offense of unlawful use of weapons when he knowingly:
(1) Sells, manufactures, purchases, possesses or carries any bludgeon, black-jack, slung-shot, sand-club, sand-bag, metal knuckles or other knuckle weapon regardless of its composition, throwing star, or any knife, commonly referred to as a switchblade knife, which has a blade that opens automatically by hand pressure applied to a button, spring or other device in the handle of the knife, or a ballistic knife, which is a device that propels a knifelike blade as a projectile by means of a coil spring, elastic material or compressed gas; or
(2) Carries or possesses with intent to use the same unlawfully against another, a dagger, dirk, billy, dangerous knife, razor, stiletto, broken bottle or other piece of glass, stun gun or taser or any other dangerous or deadly weapon or instrument of like character; or
(3) Carries on or about his person or in any vehicle, a tear gas gun projector or bomb or any object containing noxious liquid gas or substance, other than an object containing a non-lethal noxious liquid gas or substance designed solely for personal defense carried by a person 18 years of age or older; or
(4) Carries or possesses in any vehicle or concealed on or about his person except when on his land or in his own abode or fixed place of business any pistol, revolver, stun gun or taser or other firearm, except that this subsection (a)(4) does not apply to or affect transportation of weapons that meet one of the following conditions.
Illinois State law does not require that knives be concealed in order to be a violation. The statute provides that dangerous knives are prohibited if one “carries or possession with the intent to use the same unlawfully against another.” The absence of the term “concealed in subsection 2 appears to be deliberate, as the legislature included the term “concealed” in subsection 4. Further, Illinois courts have provided little guidance regarding what is a “dangerous knife.” Rather the cases that do exist tend to focus on whether the individual possessed a knife with the intent to use illegally against another. Notable is People v. Sullivan, where the defendant was carrying a sheathed hunting knife (and I presume to be a fixed blade). The court held that:
The convictions for unlawful use of weapons required proof that the knives were carried or possessed ‘with intent to use the same unlawfully against another. The State argues that the requisite intent may be proved by the surrounding circumstances, citing People v. Shields, 6 Ill.2d 200, 205, 127 N.E.2d 440, where it was held that intent to murder can be inferred from the character, manner, and circumstances of an assault. We agree, of course, with the general proposition that criminal intent may be inferred from circumstantial factors. But the circumstances here do not reasonably establish intent to use the hunting knives against another. The State's position appears to be that no other theory can reasonably explain the possession of hunting knives late at night in a residential area. While the State's point that use of the knives for hunting purposes does not appear to have been the intent of the defendants, Jenkins and Dougherty, must be admitted, one cannot conclude from this that Jenkins and Dougherty intended unlawfully to use the knives against another. Were such a conclusion to be drawn it would be in effect a holding that the statute prohibited the carrying of a hunting knife for any purpose other than for the purpose of hunting. No prohibition exists; simple possession of a hunting knife is not criminal. The legislature has specifically named the weapons, the simple possession of which is Per se unlawful. Subsection (a)(1) of the unlawful use of weapons statute prohibits the possession of a switchblade knife, sawed-off shotgun, brass knuckles, blackjack, Etc., but as to a hunting knife proof of intent to use it unlawfully against another is essential. It is the proof of that intent, or circumstances from which such intent is reasonably inferable, that is missing here. Thus, affirming the convictions cannot be justified where the weapons are not contraband, and no evidence reasonably establishes an intent to use the weapons unlawfully against another.
