S.C. Code Ann. § 5-3-140

If the territory proposed to be annexed belongs entirely to the federal government or to the State of South Carolina and is adjacent to a municipality, it may be annexed upon the petition of the federal government or of the State to the city or town council thereof. As used in this section, a petition by the State shall mean a petition executed by the State Fiscal Accountability Authority. Upon agreement of the city or town council to accept the petition and the passage of an ordinance to that effect, the annexation is complete.