In 1865, the United States (plaintiff) created the Colorado River Indian reservation and offered to construct a canal for irrigation as a compromise for those tribes who lived within the reservation and waived claims to land outside it. The Hualapai (also spelled Walapai) did not accept and remained on ancestral lands outside the reservation. The next year, the government granted land that overlapped the Hualapais to the predecessor of the Santa Fe Pacific Railroad Company (defendant). In 1874, the government forcibly removed the Hualapai to the Colorado River reservation, but the entire tribe left the following year and returned to their ancestral lands. The government let them remain “during good behavior.” In 1881, the Hualapais asked for a reservation for the tribe. The president signed an order reserving the Walapai Indian Reservation, which the Hualapais accepted. Decades later, the U.S. sued on the Hualapais’ behalf to enjoin the railroad from interfering with the tribe’s occupancy rights based on aboriginal title to land both within and beyond the boundaries of the reservation. The railroad countered that the government had never recognized the Hualapais’ aboriginal title, and that various legislative acts had extinguished it. The trial and appellate courts found for the railroad, and the government appealed to the United States Supreme Court.