43 C.F.R. § 2310.3-4
(a) An order initially withdrawing 5,000 or more acres of land in the aggregate, on the basis of the Secretary's authority under section 204 of the Act (43 U.S.C. 1714), may be made for a period not to exceed 20 years from the date the order is signed, except that withdrawals exceeding 5,000 acres in the State of Alaska shall not become effective until notice is provided in the Federal Register and to both Houses of Congress. All orders withdrawing 5,000 or more acres in the aggregate shall be subject to the Congressional review provision of section 204(c) of the Act (43 U.S.C. 1714(c)), except as follows:
(b) An order initially withdrawing less than 5,000 acres of land, in the aggregate, on the basis of the Secretary's authority under section 204 of the Act (43 U.S.C. 1714), may be made: