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 Montana, criminal trespassing is defined under Montana Code Annotated (MCA) 45-6-203. A person commits the offense of criminal trespass to property if they knowingly enter or remain unlawfully on the property of another. This includes various types of property such as residential, agricultural, recreational, as well as buildings and vehicles. The law specifies that a person must either have had notice that entry was forbidden or, if they were on the property lawfully, they must have received notice to depart and failed to do so. Penalties for criminal trespass in Montana can range from fines to imprisonment, depending on the severity of the trespass and whether it involved damage to property or other aggravating factors. It is important for individuals to understand that consent is a key element in determining whether an act constitutes trespassing. Without consent, entering or remaining on someone else's property can lead to criminal charges.