This Executive Order, issued by President Ulysses S. Grant on April 12, 1870, established the Fort Berthold Reservation. In addition to Grant’s Executive Order, this document includes a series of letters, proposals, and endorsements for the creation of a reservation for the Mandan, Hidatsa, and Arikara. Importantly, this document also contains the original map outlining the proposed boundaries and the president’s diagram which significantly reducing the size of the reservation.https://commons.und.edu/indigenous-gov-docs/1195/thumbnail.jp
