Oak Island, North Carolina is a town located mostly on Oak Island (which also contains the town of Caswell Beach and the North Carolina Baptist Assembly at Fort Caswell) in Brunswick County, North Carolina, United States; a small part of the town extends onto the mainland north of the island's bridge. The population was 6,571 at the 2000 census. It was founded in 1999 by the consolidation of the towns of Long Beach and Yaupon Beach. Its main industry is tourism; the town has an average summer population of 30-40,000. Oak Island is part of the Wilmington Metropolitan Statistical Area.