Leigh-on-Sea was recorded in the Domesday Book of 1086 as Legra, where it is described as a "one horse town". Located next to the sea, Leigh has been primarily a fishing village for most of its history.

Due to its good position on the shipping route to London, it began to grow and by the 16th century had become a fairly large and prosperous port and with its location at the mouth of the Thames, Leigh was often used by the navy against threats from pirates and the French, Spanish and Dutch Navies.

The fishermen of Leigh are famous for their heroic attempts to rescue British soldiers stranded on the beaches of Dunkirk. A memorial in St Clements churchyard stands as a reminder of their bravery and sacrifice.

Leigh-on-Sea boasts London's nearest beach, and many visitors travel down at the weekend to the conservation area of Old Leigh with its cobbled streets and clapboard cottages. The area is notable for its shellfish, and there is a small but active fleet of cockle boats, which keep alive the reputation of Leigh as the epicentre of the world cockling trade. The picturesque cockle sheds are home to many old Leigh families who have followed this trade for generations.