S.C. Code Ann. § 3-3-290

A lot on South Island in Georgetown County, on the southern edge of Winyah Entrance, has been ceded to the United States for a lighthouse. Such lot shall, during the continuance of such lighthouse, be exempt from any taxes to be paid to this State. But such lot and every person and officer residing or employed thereon, whether in the service of the United States or not, shall be subject and liable to the government of this State and the jurisdiction, laws and authority thereof in the same manner as if this cession had never been made and the United States shall exercise no more authority or power within the limits of said land than it might have done previous to the cession thereof or than may be necessary for the building, erection, repairing or internal government of the lighthouse and of the officers and persons by the United States to be employed in and about the same.