This short article answers three commonly asked questions about the reservation: (1) Who are the Eastern Shoshone and Northern Arapaho Indians? (2) If the reservation was set aside for the Shoshones, when did the Arapahos arrive and why are they there? (3) How does a reservation function? Shoshone Prehistory While the Arapahos have more members (over 9,000+ compared to the Shoshones’ 4000+ members), the reservation was created for the Eastern Shoshones (and Bannocks) in 1868. It is home for the Eastern Shoshone and Northern Arapaho tribes. The Wind River Indian Reservation contains over 2.2 million acres located in the central part of the state. Like many western states, Wyoming has an Indian reservation within its borders.