This is one of two forts established by order of Maj. Gen. John Pope on the Bozeman Road in 1866. Col. H. B. Carrington was commissioned to select the sites and build Forts Phil Kearny and C. F. Smith. The former was staked off on July 15, 1866, and the latter, ninety miles northwest, in Montana, early in August. Fort Phil Kearny was completed on the 21st of October and for several months the posts and the country immediately surrounding it were the scene of several conflicts with the hostile Indians. An account of the massacre of Capt. W. J. Fetterman and his command on December 21, 1866, is given in the chapter on Early Military History.
On March 2, 1868, Gen. U. S. Grant issued an order for the abandonment of all the forts on the Bozeman Road and the withdrawal of all troops from the Indian country in Northern Wyoming. Fort Phil Kearny was abandoned under this order in August, 1868, and the buildings were afterward burned by the chief Little Wolf. A monument commemorating the Fetterman Massacre was unveiled on the site of the fight on July 4, 1908. The massacre occurred seven miles from the fort, which was located on Piney Creek, four miles from the Big Horn Mountains and about fifteen miles northwest of the present City of Buffalo. After the fort was abandoned, George Geier purchased that part of the reservation where the buildings formerly stood and established thereon a ranch.
Source: History of Wyoming, Volume 1, by I. S. Bartlett, Chicago, The S. J. Clarke Publishing Company, 1918