43 U.S.C. § 18

Whenever any person claiming to be interested in or entitled to land, under any grant or patent from the United States, applies to the Department of the Interior for copies of papers filed and remaining therein, in anywise affecting the title to such land, it shall be the duty of the Secretary of the Interior to cause such copies to be made out and authenticated, under his hand and the seal of the Bureau of Land Management, for the person so applying.