Dawes Act

The Dawes Act of 1887 authorized the President of the United States to survey and divide Native American lands for individuals. Any Native American living on these allotments, outside of reservations, would then be granted citizenship. The goal of the Dawes Act was to facilitate the assimilation of Native Americans into mainstream society, but wound up creating numerous negative effects, including the communal holding of land by Native Americans and reduced Native land holdings from 138 million acres in 1887 to a mere 48 million acres by 1934.
Although many Native Americans had been forced onto reservations by the US government, by the 1880s it was feared that they posed a threat to America by their clinging to traditional ways of life. The Dawes Act, signed into law by Grover Cleveland, had six goals: to break up tribes as a social unit, to encourage individualism, to help Native American farmers, to reduce the cost of administration of Indian Affairs, to secure parts of reservations for Native Americans, and to open leftover land for white settlers.
Much of the land allotted to Native Americans in the Great Plains region under the Dawes Act was unsuitable for farming. Much of that land was eventually sold to non-Native Americans, resulting in large numbers of Native Americans becoming landless. The Dawes Act also forced European patriarchy onto many Native American societies that were largely matrilineal.