The Fetterman Fight is a battle during Red Cloud's War on December 21, 1866, between the Lakota Sioux, Cheyenne, and Arapaho Indians and soldiers of the United States army.

All 81 men under the command of Captain William J. Fetterman are killed by the Indians.

It is, at the time, the worst military disaster ever suffered by the U.S. on the Great Plains.

The battle leads to an Indian victory in the war and the withdrawal of the United States from the Powder River country of Montana and Wyoming.The Fetterman Fight is also known as the Fetterman Massacre, the Battle of the Hundred Slain, and the Battle of the Hundred in the Hand.