Warriors enlisted as Pawnee Scouts in the latter half of the 19th century in the United States Army. Like other groups of Native American scouts, Pawnee warriors were recruited in large numbers to fight on the Northern and Southern Plains in various conflicts against hostile Native Americans. Because the Pawnee people were old enemies of the Sioux, Cheyenne, Arapaho, Comanche, and Kiowa tribes, they served with the army for 14 years between 1864 and 1877, earning a reputation as being a well-trained unit, especially in tracking and reconnaissance. The Pawnee Scouts took part with distinction in the Battle of the Tongue River during the Powder River Expedition (1865) against Lakota, Cheyenne, and Arapaho and in the Battle of Summit Springs. They also fought with the US in the Great Sioux War of 1876. On the Southern Plains, they fought against their old enemies, the Comanches and Kiowa, in the Comanche Campaign.