Effective August 9, 2017, the restrictions on automatic or gravity knives has been removed from the definition of illegal weapons § 18-12-102. Still illegal as a dangerous weapon is a ballistic knife definied in § 18-12-101 as:
Ballistic knife means any knife that has a blade which is forcefully projected from the handle by means of a spring-loaded device or explosive charge..
Carrying a concealed knife in Colorado with a blade in excess of three-and-one-half inches (3½) in length is a violation of law. The Colorado concealed weapon statute provides that it is a crime to carry a knife concealed on or about the person.§ 18-12-105(1)(a). Knife is statutorily defined as follows:
Knife means any dagger, dirk, knife, or stiletto with a blade over three and one-half inches in length, or any other dangerous instrument capable of inflicting cutting, stabbing, or tearing wounds, but does not include a hunting or fishing knife carried for sports use. The issue that a knife is a hunting or fishing knife must be raised as an affirmative defense.
Affirmative defense means that the burden on the knife owner to prove that he or she was carrying a knife for sports use and that the knife qualifies as a hunting or fishing knife.
It is legal to carry a knife with a blade length of less than three-and-one-half (3-1/2) inches either openly or concealed. The Colorado Supreme Court has interpreted the unlawful carrying statute as prohibiting the conviction of a person for carrying a knife with a blade less than three-and-one-half inches (3½) in length, absent proof that the person intended to use the knife as a weapon. Moreover, such intent cannot be inferred solely from the appearance of the knife in question. A.P.E., a Juvenile v. The PEOPLE of the State of Colorado, 20 P.3d 1179 (Colorado Supreme Court 2001).
Three-and-a-half inches“any blade length longer than three-and-a-half inches is a knife, which cannot legally be carried concealed, with specific exceptions for hunting, fishing or sport use.
Section 18-12-105.6 offers limited protection to knife owners by providing that state law prevails when someone is traveling in a private vehicle or other private means of transportation. However, if you are not traveling in a private vehicle, local laws may apply.
Deadly weapons may not be possessed on school grounds. This applies to all educational levels, elementary through university (K through post-graduate)§ 18-12-105.5 For purposes of this section, the definition of deadly weapon includes a knife (a defined term as set forth above). There are several exceptions, including a knife stored inside a vehicle.
This information is presented as a brief synopsis of the law and not as legal advice.