Adverse possession
Adverse possession in common law, and the related civil law concept of usucaption (also acquisitive prescription or prescriptive acquisition), are legal mechanisms under which a person who does not have legal title to a piece of property, usually real property, may acquire legal ownership based on continuous possession or occupation without the permission (license) of its legal owner. At common law, there was no requirement adverse possession claims be made in good faith, meaning that an adverse possessor was not required to prove that they subjectively believed they were entitled to the property.