S.C. Code § 3-3-70
The right, title and interest of the State to, and the jurisdiction of this State over, the following described lot or parcel of land has been granted and ceded to the United States for the erection of a public building, to wit: All that certain piece, parcel or lot of land situate, lying and being in the city of Aiken, in Aiken County, beginning at the southwest corner of Park Avenue and Laurens Street, running thence southerly with the west line of Laurens Street one hundred and forty feet; thence westerly at right angles with Laurens Street one hundred and twenty feet; thence northerly, parallel with Laurens Street, one hundred feet, more or less; thence easterly with Park Avenue one hundred and twenty feet, more or less, to the point of beginning.
Jurisdiction and service of process. Exclusive jurisdiction in and over said lot or parcel of land, when acquired by the United States, was ceded to the United States for the purposes mentioned except the service upon such sites of all civil and criminal processes of the courts of this State; but the jurisdiction so ceded shall continue no longer than the United States shall own such piece of land.
Condition of cession; exemption from taxes. Such jurisdiction was so ceded on condition that it would not vest until the United States acquired the title to such land by purchase from its owner. So long as the lot or parcel of land shall remain the property of the United States when so acquired and no longer it shall be and continue exempt and exonerated from all State, county and municipal taxation, assessments or other charges which may be levied or imposed under the authority of this State.
S.C. Code § 3-3-70