They were close allies of the Cheyenne tribe and loosely aligned with the Lakota and Dakota.īy the 1850s, Arapaho bands formed two tribes, namely the Northern Arapaho and Southern Arapaho. The Arapaho ( / ə ˈ r æ p ə h oʊ/ ə- RAP-ə-hoh French: Arapahos, Gens de Vache) are a Native American people historically living on the plains of Colorado and Wyoming.