The Grattan Massacre occurred in what is today Nebraska, USA on August 17, 1854 near Fort Laramie, in which a number of US soldiers were killed by Brule Sioux. This then lead to the Battle of Bluewater Creek (also known as the Battle of Ash Hollow) on September 3, 1855, in which US soldiers killed a number of Brule Sioux near Ash Hollow on Bluewater Creek. It was an early event in the plains Indian wars and was significant as Crazy Horse was present as a young child and deeply influenced by the events.

Grattan Massacre

In the late summer of 1854 about 4,000 Brule and Oglala Sioux were camped near Fort Laramie in accordance with the terms of an earlier peace treaty. On August 17th a cow, belonging to a Mormon who was traveling on the Oregon Trail nearby, wandered into the Sioux camp, and the wayward cow was killed.

Brevet 2nd Lt. John L. Grattan, a recent graduate of West Point, was ordered to bring in the guilty Sioux cow killer. Grattan was an inexperienced and quick to anger young man who was looking for a fight with the Indians to prove himself. A commander at Laramie later recalled "There is no doubt that Lt. Grattan left this post with a desire to have a fight with the Indians, and that he had determined to take the man at all hazards."

In a foolish spectacle in front of the Brule chief Conquering Bear, Grattan insisted on taking the guilty party in to custody. Conquering Bear understood the nature of the situation and tried to negotiate but Grattan continued to escalate tensions. When Conquering Bear stood up in despair at the brash young man, he was shot in the back and killed. This started a volly of fire from both sides and Grattan and all of his men were killed. This event was called the Grattan Massacre by the US media as part of a campaign to stir up anti-Indian sentiment.

News of the "massacre" reached the War Department and plans were put in to motion for retaliation. William S. Harney was recalled from Paris and sent to Fort Kearny where he was put in command of elements of his own 2nd Dragoons and units from the 6th and 10th Infantry and the 4th Artillery Regiments. They set out on August 24th, 1855 to find and exact payment on the Sioux.

Battle of Bluewater Creek

On September 3rd on the Blue Water Creek, near Ash Hallow, the 600 soldiers found the 250 Sioux men, women and children. Little Thunder had taken over as chief after Conquering Bear's death. Harney had declared days earlier "By God, I'm for battle—no peace". It was with that he ordered his men to open fire on the community of Sioux. 85 Brules were killed, including some women and children.

Afterwards the Army made a wide sweep of the surrounding Sioux country but encountered no further resistance. For his handling of the battle at Ash Hollow, Harney was known afterwards among the Sioux as "the Butcher." Crazy Horse was a child at the massacre and survived; he had a spiritual vision foretelling of his future as a warrior.

For military officials and the increasing numbers of emigrants traveling the Oregon Trail, the battle bought them 10 more years of relative peace.