From September 3-5, 1863, Brigadier General Alfred Sully led U.S. Army troops against a village of Yanktonai, Santee, and Teton (Lakota) Sioux.

[2] This caused about 4,000 Santee to flee from Minnesota to Dakota Territory where they united with other elements of the Yanktonai, Yankton, and Lakota or Teton Sioux.

In mid-1863, the United States Army under General John Pope in Minnesota mounted two large military expeditions against the Sioux in eastern Dakota Territory.

The objectives of the expeditions were to prevent a renewal of the 1862 war, promote white settlement in the eastern Dakotas, and protect access to the Montana goldfields via the Missouri River.

Although Sibley's men did not inflict heavy casualties, they pushed the Sioux to the western side of the Missouri River and destroyed much of their property including winter supplies of jerky and many of their tipis.

[4] The second prong of the operation was led by Sully who was supposed to ascend the Missouri River with 1,200 men, rendezvous with Sibley, and crush the Sioux between the two forces.

[5] When Sully arrived in the vicinity of present-day Bismarck, North Dakota in mid-August, Sibley had already returned to Minnesota.

[9] Sully ordered his advance force, a battalion of the Sixth Iowa numbering 300 men under Major A. E. House to surround the encampment and prevent the Indians from leaving.

He left four companies to guard his supply train and then advanced with his main force at a gallop covering the 10 miles in one hour.

[10] While Major House and his battalion of the Sixth Iowa were scouting the Indian camp and waiting for Sibley to come forward with additional soldiers, a delegation from the Sioux advanced with a white flag constructed from a flour sack,[11] claimed to be peaceful and only interested in hunting, and offered to surrender several of their chiefs.

However, in his haste he failed to order some of his men to load their weapons and heavy fire from the Sioux caused the cavalry horses to bolt and the charge to break down.

On the left, Colonel Furnas also withdrew his Nebraskans to a defensive position, fearing friendly fire and losing control of his soldiers in the increasing darkness.

A patrol of 27 soldiers commanded by Lt. Charles W. Hall encountered an estimated 300 Sioux about fifteen miles from Whitestone Hill.

Despite the deliberate targeting and execution of children and infants, the substantial casualties of the soldiers demonstrate, according to Micheal Clodfelter, that Whitestone Hill was a battle, not a massacre.

[20] Due to the poor condition of his horses and mules and his lack of supplies, Sully was unable to pursue the Sioux.

He left Whitestone Hill on September 6 and marched his men to Fort Pierre in present-day South Dakota.