Hanahan is a city in Berkeley County, South Carolina, United States. The population was 12,937 at the 2000 census. Portions of the Naval Weapons Station Charleston, including the Naval Consolidated Brig Charleston, are located in Hanahan. As defined by the U.S. Office of Management and Budget, and used by the U.S. Census Bureau for statistical purposes only, Hanahan is included within the Charleston-North Charleston-Summerville metropolitan area and the Charleston-North Charleston Urbanized Area
Hanahan is located on the very south end of Berkeley County, and its city limits on the west and south sides are contiguous with the county line between Berkeley and Charleston Counties. It was incorporated as a city in 1972.
Hanahan is bordered on the west and south by the city of North Charleston, South Carolina. To the east is the old Naval Weapons Station, which was formerly a submarine base, and is still federal property. A very small portion of this federal base is actually in Hanahan's city limits. Among other uses of the former submarine base, the Naval Consolidated Brig is there, as is the Navy's Nuclear Power School. To the north is an unincorporated portion of Berkeley County.