A person commits the offense of criminal trespass or criminal trespassing by entering or remaining on the property of another—including residential land, agricultural land, recreational land (such as a vehicle park), a building, an aircraft, or an automobile—without consent and if the person (1) had notice that the entry was forbidden, or (2) received notice to depart, but failed to do so.

The definitions and penalties for criminal trespassing vary from state to state and are usually located in a state’s penal or criminal code (statutes).

In California, criminal trespass is defined under Penal Code 602 PC. This law states that a person commits the offense of criminal trespass by entering or remaining on someone else's property without permission or a right to do so. The individual must have either been aware that they were not allowed to enter (e.g., through signs, fencing, or verbal warnings) or, if they were initially allowed, they must have refused to leave after being asked to depart by the owner, the owner's agent, or by law enforcement. Penalties for criminal trespass in California can vary depending on the circumstances and the severity of the offense. They can range from a simple infraction to a misdemeanor. Misdemeanor trespass can result in penalties including fines up to $1,000 and/or imprisonment in county jail for up to six months. In some cases, if the trespass is associated with a threat to injure a person on the property, it can be charged as a felony, leading to more severe penalties.