The US government passed all of the Indian Appropriation Acts during the 1850-1880s.
The first act was passed in 1851, which financed funds to move western tribes onto reservations. The second act was passed in 1871, which stated that the Indians were not longer to be able to be considered in the United States as an independent nation. The third act was passed in 1885, which allowed the Indians to sell/buy unoccupied land. The fourth act was passed in 1889, which gave the white settlers unassigned land.