Canvey Island is a town, civil parish and island in the Thames Estuary. It forms part of the Castle Point district of Essex, England. It is separated from the mainland of south Essex by a network of creeks, but is connected to the mainland by bridges. It has an area of 7.12 square miles (18.44 km2). At the 2021 census the parish had a population of 38,327 and the built up area had a population of …