Battle of Summit Springs
1869 CE.
Shown on the map at 40.433°, -103.139°.
The Battle of Summit Springs, on July 11, 1869, was an armed conflict between elements of the United States Army under the command of Colonel Eugene A. Carr and a group of Cheyenne Dog Soldiers led by Tall Bull, who was killed during the engagement. The US forces were assigned to retaliate for a series of raids in north-central Kansas by Chief Tall Bull's Dog Soldiers band of the Cheyenne. The battlefield is located south of today's Sterling, Colorado, in Washington County near the Logan/Washington county line.
Text from the Wikipedia article Battle of Summit Springs, licensed CC BY-SA 4.0.