The Battle of Round Mountain was the first battle in the Trail of Blood on Ice campaign for the control of Indian Territory during the American Civil War that occurred on November 19, 1861. Its main purpose was to prevent Union supporters of the Creek Nation, led by Opothleyahola from fleeing Indian Territory to the protection of Union forces in Kansas.

The physical location of the battle is in dispute. Some historians believe it to be near Keystone while others contend that it is near Yale, Oklahoma. The event is sometimes referred to as the Battle of Red Fork.

Events

Col. Douglas H. Cooper, Confederate commander of the Indian Department, was unable to reconcile differences with Opothleyahola, commander of a band of Unionist Creeks and Seminoles. Opothleyahola's group was estimated to number about seventeen hundred people, and also included some Union supporters from the Comanches, Delawares, Kickapoos, Wichitas, and Shawnees. Cooper set out on November 15, 1861, with about 1,400 men either to compel Opothleyahola's submission or "drive him and his party from the country." Cooper's force rode up the Deep Fork of the Canadian River to find Opothleyahola's camp deserted. On November 19, Cooper learned from captured prisoners that part of Opothleyahola's band was erecting a fort at the Red Fork of the Arkansas River.

Cooper's men arrived there around 4:00 p.m. Charging cavalry discovered that Opothleyahola's followers had recently abandoned their camp. The Confederates located and followed stragglers; the 4th Texas blundered into Opothleyahola's warriors on the tree line at the foot of the Round Mountains. The Federal response chased the Confederate cavalry back to Cooper's main force. Darkness prevented Cooper's counterattack until the main enemy force was within . After a short fight, Opothleyahola's men set fire to the prairie grass and retreated.

The following morning, Cooper advanced on Opothleyahola's new camp but found that the Federal forces had fled. The Confederates claimed victory because Opothleyahola had left the area. The Confederates captured abandoned supplies, such as Opothleyahola's carriage, a dozen wagons, food, cattle and ponies. The Confederate loss in the engagement was 1 captain and 5 men killed, 3 severely and 1 slightly wounded, and 1 missing. Opothleyahola lost about 110 killed and wounded.