The Great Sioux War of 1876–77 began at daybreak on March 17, 1876, when Colonel Joseph J. Reynolds and six cavalry companies struck a village of Northern Cheyennes—Sioux allies—thereby propelling the Northern Plains tribes into war. The ensuing last stand of the Sioux against Anglo-American settlement of their homeland spanned some eighteen months, playing out across more than twenty battle and skirmish sites and costing hundreds of lives on both sides and many millions of dollars. And it all began at Powder River. Powder River: Disastrous Opening of the Great Sioux War recounts the wintertime Big Horn Expedition and its singular great battle, along with the stories of the Northern Cheyennes and their elusive leader Old Bear. Historian Paul Hedren tracks both sides of the conflict through a rich array of primary source material, including the transcripts of Reynolds’s court-martial and Indian recollections. The disarray and incompetence of the war’s beginnings—officers who failed to take proper positions, disregard of orders to save provisions, failure to cooperate, and abandonment of the dead and a wounded soldier—in many ways anticipated the catastrophe that later occurred at the Little Big Horn. Forty photographs, many previously unpublished, and five new maps detail the action from start to ignominious conclusion. Hedren’s comprehensive account takes Powder River out of the shadow of the Little Big Horn and reveals how much this critical battle tells us about the army’s policy and performance in the West, and about the debacle soon to follow.