Fort Berthold Indian Reservation

The Fort Berthold Indian Reservation is a U.S. Indian reservation in western North Dakota that is home for the federally recognized Mandan, Hidatsa, and Arikara Nation, also known as the Three Affiliated Tribes. Created in 1870, the reservation is a small part of the lands originally reserved to the tribes by the Fort Laramie Treaty of 1851, which allocated nearly 12 million acres (49,000 km²) in North Dakota, South Dakota, Montana and Wyoming.