Art 1 Sec 8, 17th enumerated power;
17: 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 the 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
Exactly. I keep looking for the “vast national parks” and “vast government land holdings” section of the constitution, and I keep running into the first amendment before I find the “vast holdings” clause.