S.C. Code Ann. § 3-3-60

One acre of land on Otter Island in Colleton County has been ceded to the United States for a lighthouse, one acre of land on the north side of Station Creek, near St. Helena Island, in Beaufort County has been ceded to the United States for the erection of a beacon light and one acre of land on Bob's Island, at the entrance of Scull Creek, in Beaufort County has been ceded to the United States for the erection of a beacon light. But said lands and every person or 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 the cession had never been made and the United States shall exercise no more authority or power within the limits of such lands than it might have done previously to the cession thereof or than may be necessary for the building, erection, repairing or internal government of the lighthouse and the regulation and management of the lighthouse and the beacon lights that may be built and erected on such lands and of the officers and persons by them to be employed in and about the same. Such lands shall be forever exempt from any taxes to be paid to this State.