Sullivan's Island is a barrier island in Charleston County, South Carolina, at the entrance to Charleston Harbor. The population was 1,911 at the 2000 census. It is also the site of a major battle of the American Revolution at Fort Sullivan on June 28, 1776. As defined by the U.S. Census Bureau, Sullivans Island is included within the Charleston-North Charleston Urbanized Area and the larger Charleston-North Charleston Metropolitan Statistical Area. Sullivan's Island apartments for rent comparison page shows most up to date rent information on Sullivan's Island apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.