ORDER OF BATTLE // July 28, 1864
Battle of Killdeer Mountain
Estimated force strength by side, with confidence labels per surviving record.
Forces engaged
2 sides catalogued · combined 3,800 estimated
United States of America
2,200
Medium-confidence figure
Lakota
1,600
Medium-confidence figure
Battle context
The Battle of Killdeer Mountain was fought during Brigadier General Alfred Sully's 1864 expedition against the Sioux in Dakota Territory, conducted in what is now Dunn County, North Dakota. The engagement was part of an operation involving more than 4,000 soldiers in total, making Sully's expedition the largest the U.S. Army had mounted against Native Americans to that point. With over 2,200 troops committed at Killdeer Mountain itself, the battle represented a significant escalation of federal military pressure on Lakota bands in the Northern Plains during the broader Sioux Wars. Among the Lakota leaders present were Gall, Sitting Bull, and Inkpaduta, figures who would remain central to Lakota resistance in the decades that followed. The scale of the operation signaled a shift in U.S. strategy toward large-scale conventional expeditions into Sioux territory, setting a precedent for subsequent campaigns in the region.
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