The Fort Robinson breakout or Fort Robinson massacre was the attempted escape of Cheyenne captives from the U.S. army during the winter of 1878-1879 at Fort Robinson in northwestern Nebraska. In 1877, the Cheyenne had been forced to relocate from their homelands on the northern Great Plains south to the Darlington Agency on the Southern Cheyenne Reservation in Indian Territory (Oklahoma). In September 1878, in what is called the Northern Cheyenne Exodus, 353 Northern Cheyenne fled north because of poor conditions on the reservation. In Nebraska, the U.S. Army captured 149 of the Cheyenne, including 46 warriors, and escorted them to Fort Robinson.