Trespass is the wrongful act of going onto someone else's land, or placing an object on the land, without the permission of the owner or remaining on land after permission has been revoked. It is a crime, though usually only prosecuted if the trespasser refuses to leave after being told to do so.
Trespass is also a tort. Under tort law, trespassing is separated into two branches: trespass to land and trespass to chattels. The tort of trespass to land is generally the same as a criminal trespass. The owner can sue for damages regardless of whether the trespasser realized that he was on someone else's land. This tort reflects the view of the English common law that property ownership is absolute. Trespass to chattels is a minor interference with a person's ownership or use of personal property. More severe interference constitutes conversion.