Khlong San was called, in chronological order, Amphoe Bang Lamphu Lang , Amphoe Buppharam , and Amphoe Khlong San (since 1916) when it was part of Thonburi Province. Its status was changed to king amphoe in 1938 and back to amphoe again in 1957 due to population changes. It became part of Bangkok after the merging of Thonburi and Phra Nakhon Provinces in 1971. Khlong San was originally the terminus of the Maeklong Railway, but the line was cut back to Wongwian Yai in 1961 to ease traffic congestion.