In common law, the curtilage of a house or dwelling is the land immediately surrounding it, including any closely associated buildings and structures, but excluding any associated "open fields beyond". In feudal times every castle with its dependent buildings was protected by a surrounding wall, and all the land within the wall was termed the curtilage. The term excludes any closely associated buildings, structures, or divisions that contain the separate intimate activities of their own respective occupants, with those occupying residents being persons other than those residents of the house or dwelling of which the building is associated.
In some legal jurisdictions, the curtilage of a dwelling forms an exterior boundary, within which a home owner can have a reasonable expectation of privacy and where "intimate home activities" take place. It is a basic legal concept underlying the concepts of search and seizure, conveyancing of real property, burglary, trespass, self-defense, and land use planning.
In urban properties, the location of the curtilage may be self-evident from the position of fences or walls. For larger, more rural properties, it may be a matter of debate as to where the private area ends and the "open fields" start.
The word derives from courtelage; cortillage or cortil ("court, yard, garden"); cort (court) + -il (diminutive suffix) + -age (suffix indicating a state of being).
At common law, which derives from English law, curtilage has been defined as "the open space situated within a common enclosure belonging to a dwelling-house." Black's Law Dictionary of 1891 defined it as:
"The enclosed space of ground and buildings immediately surrounding a dwelling-house. In its most comprehensive and proper legal signification, it includes all that space of ground and buildings thereon which is usually enclosed within the general fence immediately surrounding a principal messuage and outbuildings, and yard closely adjoining to a dwelling-house, but it may be large enough for cattle to be levant and couchant therein.