borough (district), administrative and historic county of Essex, eastern England, on the north side of the River Thames near its mouth. Castle Point is a low-lying borough of tidal inlets and reclaimed land protected by embankments and dikes. The parishes (towns) of Canvey Island to the south and Benfleet on the mainland to the north experienced rapid residential growth in the 1960s and 1970s. Canvey Island, the nearest seaside resort to London, has a great many summer cottages and camper hookup sites. Boating is especially popular in the vicinity.

Printing, engraving, and furniture-making industries and some market gardening are based in Castle Point. Canvey Island has facilities for the storage of liquefied natural gas and for refining petroleum. The borough derives its name from the local medieval Hadleigh Castle, which the artist John Constable made the subject of a powerful landscape. The borough seat is at Thundersley within Benfleet town. Area 17 square miles (45 square km). Pop. (2001) 86,614.