South Benfleet is a town in the Castle Point district of Essex, England, 30 miles east of London. It is adjacent to the village of North Benfleet. The Benfleet (SS7) post town includes South Benfleet, Thundersley, New Thundersley and Hadleigh. The Battle of Benfleet took place here between the Vikings and Saxons in 894.

Castle Point is a local government district with borough status in south Essex, England, lying around 30 miles (48 km) east of London. The borough comprises the towns of South Benfleet, Hadleigh and Thundersley on the mainland, and the adjoining Canvey Island in the Thames Estuary, which is connected to the mainland by bridges.