Trespassing is a legal term that can refer to a wide variety of offenses against a person or against property. Trespassing as it relates to real estate law means entering onto land without consent of the landowner. There are both criminal and civil trespass laws. Criminal trespass law is enforced by police, sheriffs, or park rangers. Civil trespass requires that the landowner initiate a private enforcement action in court to collect any damages for which the trespasser may be responsible (regardless of whether a crime has been committed).
Intent and Knowledge RequirementsTraditionally, for either type of trespass -- criminal or civil -- some level of intent is required. Thus, the trespasser must not simply unwittingly traverse another's land but must knowingly go onto the property without permission. Knowledge may be inferred when the owner tells the trespasser not to go on the land, when the land is fenced, or when a "no trespassing" sign is posted. A trespasser would probably not be prosecuted if the land was open, the trespasser's conduct did not substantially interfere with the owner's use of the property, and the trespasser left immediately on request.
The landowner may indicate -- verbally or in writing -- permission to enter onto the land.
The existence of consent may be implied from the landowner's conduct, from custom, or from the circumstances. Consent may be implied if the landowner was unavailable to give consent, and immediate action is necessary to save a life or prevent a serious injury.