The Fetterman Fight was a significant battle that took place on December 21, 1866, during the Red Cloud's War, where a U.S. Army detachment was ambushed by Lakota Sioux warriors near Fort Phil Kearny in Wyoming. This conflict highlighted the growing tensions between the United States government and Native American tribes over land and resources in the Great Plains. The event is often seen as a pivotal moment in the Plains Indian Wars, illustrating both the military challenges faced by the U.S. Army and the resilience of Native American resistance against westward expansion.