The United States government, through the Bureau of Indian affairs - which is housed in the Department of the Interior - has records on both its legal and political relationship to Indian Tribes and Alaska Native entities. Below are a list of research guides with resources to government documents on Native American topics and policies.
Photo by Byron, Elsa Spear. MOR Photo Archive. 1926. http://arc.lib.montana.edu/indian-great-plains/objects/85.13.25.jpg