The Battle of the Tongue River, sometimes referred to as the Connor Battle, was the major engagement of the Powder River Expedition of 1865, directed against the Southern Cheyenne, Arapaho and Lakota Sioux. It destroyed for a time the Arapaho capability to raid the Bozeman Trail and overland mail routes.Major General Grenville M. Dodge assumed command of the Department of the Missouri in 1865. Dodge ordered a punitive campaign to suppress the Southern Cheyenne, Sioux, and Arapaho Indians who had been conducting raids against overland mail routes. He gave tactical command of the expedition to Brigadier General Patrick Edward Connor, commander of the District of Utah.
General Connor had experienced little fighting until late August 1865, when he discovered 500 Arapaho Indians under chiefs Black Bear and Medicine Man along the Tongue River in north central Wyoming. Connor had only 400 men at his immediate disposal but moved against the Indians nonetheless. On August 29 Connor caught up to the Indian village on a piece of land where the Tongue River makes a bottleneck. Chief Black Bear and many of the warriors were away fighting the Crow along the Big Horn River, but Medicine Man and some older men, women and children were still in camp. At 0730 hours, Connor charged the village. The remaining warriors attempted to make a stand to allow the women and children to escape before the village was overrun. After the soldiers had captured the village, the Indians staged a counterattack. Connor had brought up two howitzers and held off the attack. Skirmishing lasted until dark, but the battle resulted in a victory for US forces. The Army killed or wounded 54 Indians. The soldiers captured 18 women and children, but eventually released them. Additionally, the soldiers killed over 1,000 Indian horses and ponies.