Article I, Section 8, Clause 17:
[The Congress shall have Power . . .] To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the Acceptance of Congress, become the Seat of Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings;–And . . .
This clause has been broadly construed to cover all structures necessary for carrying on the business of the National Government. 1 It includes post offices, 2 a hospital and a hotel located in a national park, 3 and locks and dams for the improvement of navigation. 4 But it does not cover lands acquired for forests, parks, ranges, wild life sanctuaries or flood control. 5 Nevertheless, the Supreme Court has held that a state may convey, and the Congress may accept, either exclusive or qualified jurisdiction over property acquired within the geographical limits of a state, for purposes other than those enumerated in clause 17. 6
After exclusive jurisdiction over lands within a state has been ceded to the United States, Congress alone has the power to punish crimes committed within the ceded territory. 7 Private property located thereon is not subject to taxation by the state, 8 nor can state statutes enacted subsequent to the transfer have any operation therein. 9 But the local laws in force at the date of cession that are protective of private rights continue in force until abrogated by Congress. 10 Moreover, as long as there is no interference with the exclusive jurisdiction of the United States, an area subject to such jurisdiction may be annexed by a municipality. 11