Powder River Expedition (1865)

Powder River Expedition
Part of the Sioux Wars, American Indian Wars
Powder River in present-day Johnson County, Wyoming north of Fort Connor
Date July 1 to October 4, 1865 Location Powder River Country, Montana, Wyoming, South Dakota, and Nebraska, United States Result inconclusive
Belligerents
United States	Sioux Cheyenne Arapaho
Commanders and leaders
Patrick E. Connor Nelson D. Cole Samuel Walker Frank North	Red Cloud Sitting Bull Roman Nose Dull Knife George Bent
Strength
2,300 soldiers, 179 Indian scouts, 195 civilians	~2,000 warriors
Casualties and losses
31 killed, 15 wounded	~100 killed, 10 wounded, 21 captured including women and children

The Powder River Expedition of 1865 also known as the Powder River War or Powder River Invasion, was a large and far-flung military operation of the United States Army against the Sioux, Cheyenne, and Arapaho Indians in Montana Territory and Dakota Territory. Although soldiers destroyed one Arapaho village and established Fort Connor to protect travelers on the Bozeman Trail, the expedition is considered a failure because it failed to defeat the Indians and secure peace in the region.

The Sand Creek massacre of Cheyenne in November 1864 intensified Indian reprisals and raids in the Platte River valley. (See Battle of Julesburg) After the raids, the Sioux, Lakota, Cheyenne and Arapaho congregated in Powder River country, remote from white settlements and confirmed as Indian territory in the 1851 Treaty of Fort Laramie.

The Indians also perceived that the Bozeman Trail, blazed in 1863 and traversing the heart of Powder River country, was a threat. Although roads through Indian territory were permitted by the Fort Laramie Treaty, the Sioux, mostly Lakota, Cheyenne, and Arapaho harassed miners and other travelers along the trail in 1864 and 1865. In July 1865, 1,000 Indian warriors in the Battle of Platte Bridge attacked a bridge across the North Platte River near Fort Caspar and succeeded in temporarily shutting down travel on both the Bozeman and the Oregon Trail. After the battle the Indians broke up into small groups and dispersed for their summer buffalo hunt. A weakness of Indian warfare was that they lacked the resources to keep an army in the field for an extended period of time.

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