Oak Island is a barrier island on the Atlantic coast of southeastern North Carolina in Brunswick County. The island contains the towns of Oak Island and Caswell Beach as well as the North Carolina Baptist Assembly and a U.S. Coast Guard station, which is home to the Oak Island Lighthouse. Although the area has been called Oak Island since colonial times, it only became a true island with the construction of the Intracoastal Waterway. It is about 12 miles long and averages about one mile wide; roughly 8000 people live on the island year-round, which can balloon up to 40,000 during the summer.