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 Illinois, criminal trespass to property is defined under 720 ILCS 5/21-3. A person commits criminal trespass when they knowingly enter or remain on the property of another without authorization. This includes residential, agricultural, and recreational land, as well as buildings and vehicles. The law specifies that a person must have either received prior notice that entry is forbidden or, if they have entered, must fail to leave upon receiving notice to depart. Penalties for criminal trespass in Illinois can vary depending on the circumstances of the offense and the type of property involved. They may range from a Class C misdemeanor, which is punishable by up to 30 days in jail and a fine, to a Class 4 felony for certain aggravated circumstances, which can carry a sentence of 1 to 3 years in prison. It is important for individuals to understand that the presence of signage or fencing can constitute legal notice of forbidden entry.