East Sussex, county (1991 pop. 670,600), 693 sq mi (1,795 sq km), extreme SE England. It comprises five administrative districts: Eastbourne, Hastings, Lewes, Rother, and Wealden. Brighton and Hove, former districts in the county, now form a single, administratively separate city. The county, the seat of which is Lewes, borders the English Channel. The South Downs form a chalky ridge on the coast, marshes line the southeast, and in the north are the Weald ridges, which are forested and comprised of clay and sand. Produce is grown, and cattle are raised. There is some light industry, but the area is mainly oriented toward tourism and resort towns that service London. William I the conqueror fought the battle of Hastings there. The remains of 12th- and 13th-century castles, churches, and abbeys are found throughout the region. See also Sussex.