Beddington lay in Wallington hundred and until the 19th century was in secular and ecclesiastical terms a large parish in its own right. Wallington was for centuries a manor in Beddington parish although in popular parlance it was the area stretching from Cheam to Addington and from Chaldon to Mitcham (inclusive). Early in the 20th century Wallington superseded Beddington's former area almost completely.
In 1901 Beddington parish consisted of 3,127.5 acres (12.657 km2), of which 1,439 acres were arable land, 614 permanent grass and 45 woods. As this was before the expansion of Wallington, it extended on the south over the chalk downs and northwards on to the London Clay. Lavender and medicinal herbs were grown commercially in the parish. The population in 1901 was 4,812. The parish was bounded on the north by Mitcham Common, and the three parishes of Croydon, Beddington and Mitcham met on the railway line by Beddington Lane station.
In 1915 Beddington and Wallington became one urban district. Prior to this both villages had been part of Croydon Rural District. The urban district proceeded to become a municipal borough in 1937. In 1965 the municipal borough was abolished and the area became part of the London Borough of Sutton in Greater London.
Beddington Park was the former manor house of the Carew family. Their story is briefly told in Wikipedia.