Coulsdon is a town located in south London, England, within the London Borough of Croydon. Historically, it served as an ancient parish in the county of Surrey that encompassed the settlements of Purley and Kenley.
The area underwent significant administrative changes over the 20th century. In 1915, it merged with Sanderstead to form the Coulsdon and Purley Urban District. The town has been part of Greater London since 1965.