The Grattan massacre triggered the First Sioux War and marked the breakdown of U.S.-Lakota treaty relations on the Great Plains.
Key Facts
- Date
- August 19, 1854
- U.S. soldiers killed
- 29 soldiers
- Location
- East of Fort Laramie, Nebraska Territory
- Conflict ignited
- First Sioux War
- Triggering incident
- Killing of a settler's cow
- Lakota chief killed
- Matȟó Wayúhi (Conquering Bear)
Location
Cause → Event → Consequence
A Mormon emigrant's cow strayed into a Sioux camp and was killed. Rather than allowing the U.S. Indian agent to resolve the dispute per treaty protocol, the Army sent a small detachment under Lieutenant John Grattan to arrest the responsible Lakota individual, escalating a minor incident into a confrontation.
On August 19, 1854, Grattan's force of 29 soldiers entered a large Sichangu Lakota camp east of Fort Laramie. When negotiations broke down, a soldier fatally shot Chief Conquering Bear. The Lakotas returned fire, killing all 29 soldiers, including Lieutenant Grattan and a civilian interpreter.
The engagement, known as the Grattan massacre, became the opening clash of the First Sioux War. It shattered the fragile peace established by the Fort Laramie Treaty of 1851 and prompted the U.S. Army to launch punitive campaigns against the Lakota Sioux across the northern Great Plains.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Lieutenant John Grattan.
Side B
1 belligerent
Chief Matȟó Wayúhi (Conquering Bear).