16 U.S.C. § 410m — Ascertainment of owners’ election regarding reservation rights

When the Secretary of the Interior acquires land or water within the area described in section 410i of this title, the Secretary must make a real effort — "reasonable diligence" — to find out whether each owner wants to keep the reservations described in section 410j of this title. Sometimes that effort fails. If the Secretary can't locate an owner, or if the owner doesn't show up in the court proceedings used to acquire the land and water, then there's no way to know whether that owner wanted to keep those reservations. In that situation, the Secretary may still acquire full, unrestricted ownership — "fee simple title" — of the land. That land is then free and clear of any of the reservations described in subsections (1), (2), and (3) of section 410j of this title.