On the morning of September 1, 1865, the over 1,400 United States soldiers and civilians, of Colonel Nelson D. Cole's column of the Powder River Expedition, were encamped on Alkali Creek, a tributary of the Powder River. This was in Montana Territory, in present-day Custer County, Montana. In the early morning, over 300 Hunkpapa, Sans Arc, and Miniconjou Lakota Sioux warriors attacked the camps' horse herd. The first of the soldiers to respond were seven men of Battery K, in the 2nd Missouri Light Artillery Regiment. Shortly after leaving the camp, warriors ambushed this party, and in the following battle, five of these seven soldiers became casualties, with two killed, one mortally wounded, and two wounded. Later that night, two unknown U.S. soldiers in a hunting party were killed. The known Sioux Casualties during the battle of Alkali Creek, are four unknown warriors killed, and four unknown warriors wounded.