43 U.S.C. § 892: Entries after expiration of grant

All such preemption and homestead entries which may have been made by permission of the Land Department, or in pursuance of the rules and instructions thereof, within the limits of any land grant at a time subsequent to expiration of such grant, shall be deemed valid, and a compliance with the laws and the making of the proof required shall entitle the holder of such claim to a patent therefor.