43 U.S.C. § 156 — Approval by Congress necessary for withdrawal, reservation, or restriction of over 5,000 acres for any Department of Defense project or facility

Starting February 28, 1958, no public land, water, or combined land-and-water area can be — without an Act of Congress — (1) withdrawn from settlement, being claimed, sold, or entered for the Department of Defense's use; (2) reserved for that use; or (3) blocked from operation of the mineral leasing rules of the Outer Continental Shelf Lands Act, if doing so would push the total amount of land withdrawn, reserved, or restricted for any single Department of Defense project or facility above five thousand acres in the aggregate. This total is measured starting from February 28, 1958, or from the last Act of Congress that withdrew, reserved, or restricted land for that same project — whichever came later. In short: small takings, added up over time, that stay under 5,000 acres do not need Congress's approval, but once a project crosses that line, only Congress can authorize more.