The River Wandle is a river in south-east England. The names of the river and of Wandsworth are thought to have derived from the Old English "Wendlesworth" meaning "Wendle's Settlement". The river runs through southwest London and is about 9 miles (14 km) long. It passes through the London Boroughs of Croydon, Sutton, Merton, and Wandsworth to join the River Thames on the Tideway at Wandsworth.