Signed on September 17, 1851, this treaty established territorial boundaries for “Dahcotah (Sioux); Gros Ventre, Mandans, and Arrickaras; Assinaboin, Blackfeet, and Crow” within lands east of the Continental Divide in present-day Montana. This treaty was not attended by the Blackfeet, but it did define their territory. No land was ceded to the U.S. from tribes located in what became “Montana”.