74 Pa. Stat. § 97
The consent of the Commonwealth of Pennsylvania is hereby given, in accordance with the seventeenth clause, eighth section, of the first article of the Constitution of the United States, to the acquisition by the United States of the aforesaid lands; and exclusive jurisdiction in and over the aforesaid lands, when acquired by the United States, is hereby ceded to the United States for all purposes except the service thereon of all civil and criminal processes of the courts of this Commonwealth; but the jurisdiction so ceded shall continue no longer than the said United States shall own such lands; and so long as the said lands shall remain the property of the United States, and no longer, the same shall be and continue exempt and exonerated from all State, county, and municipal assessment, taxation, or other charges which may be levied or imposed under the authority of this Commonwealth.
74 P.S. § 97