The Fetterman battle was fought near Fort Phil Kearny, Wyoming Territory on December 21, 1866. Angered at white interlopers traveling through their country, Sioux and Cheyenne forces continually harassed the soldiers at Fort Phil Kearny, constructed to provide emigrant protection along the newly opened Bozeman Trail. On the morning of December 21, Sioux and Cheyenne warriors were able to decoy Capt. William J. Fetterman and 80 men out of the fort and over Lodge Trail Ridge, four miles away. The carefully planned ambush worked to perfection. Fetterman and every man in his detachment died. The State of Wyoming operates the site.