South Benfleet is a town and former civil parish, now in the unparished area of Benfleet, 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, and Hadleigh. The Battle of Benfleet took place here between the Vikings and Saxons in 894. In 1951 the parish had a population of 8191. At the junction of Saint Mary's Church and The Anchor pub is the site of the UK's first "overrunable" mini roundabout.