The London Borough of Sutton () is a London borough in South London, England and forms part of Outer London. It covers an area of and is the 80th largest local authority in England by population. It borders the London Borough of Croydon to the east, the London Borough of Merton to the north and the Royal Borough of Kingston upon Thames to the north-west; it also borders the Surrey boroughs of Epsom and Ewell and Reigate and Banstead to the west and south respectively. The local authority is Sutton London Borough Council. Its principal town is the eponymous Sutton.