The Powder Ridge country of north central Wyoming was one of the most resource-rich regions of the northern plains in the nineteenth-century. As U.S. mining interests and white settlement to the north of the Montana Territory increased, conflict arose between the United States and the Lakota and Cheyenne nations. On December 21, 1866, the struggle climaxed when a well-organized force of Lakota, Cheyenne and Arapahos attacked and destroyed a detachment of infantrymen. The Battle of Where a Hundred Soldiers Were Killed or Hundred in the Hand, as the event is still called, was the worst defeat the U.S. Army had suffered in the Great Plains, only to be exceeded by the battle of Little Big Horn ten years later.