The Battle of Rush Creek took place February 8–9, 1865, between about 185 soldiers of the U.S. Army and 1,000 warriors of the Lakota Sioux, Cheyenne, and Arapaho tribes.

After the Sand Creek Massacre in November 1864 in Colorado, the Plains Indians of the three tribes in that region decided to move northward to the more isolated Powder River Country of Wyoming and Montana.

En route, they sought revenge for Sand Creek, raiding along the South Platte River in Colorado and burning the settlement of Julesburg on February 2.

Lt. Col. William O. Collins and soldiers from his command, variously reported from 140 to 185, left Mud Springs on February 8 to find the Indians, who may have numbered, with women and children, from 4,000 to 5,000.

[2] The Indians had not anticipated that the outnumbered soldiers would pursue them, and had set up their camp intending to remain there four days to rest their horses before undertaking a waterless 40-mile passage through the Nebraska Sand Hills.

The young men and women had spent all night dancing and were asleep, but were awakened suddenly at 2:00 pm, when a single Sioux warrior signaled from a hilltop that soldiers were approaching.

[3] Collins saw the large number of Indians coming his way and formed up his wagons and horses into a corral, putting his soldiers to work digging rifle pits and establishing defense lines among the sandy ridges on the plain.

[4] One group of Indians crept close enough to be a danger and Collins ordered a detail of 17 men under Lt. Patton of the 11th Ohio Cavalry to charge and disperse them.

[9] The march of the Indians north from Sand Creek to the Powder River Country was "an amazing feat," in the words of George E. Hyde.