Montana Territory
As reports of thefts of livestock and killings by Indians accumulated, the newspapers that had sprung up in the swiftly growing mining and trading communities of the Montana Territory demanded that the U.S. Army provide protection. Petitions and letters went east to Washington. In response the army established Camp Cooke on the Missouri River in the Montana Territory on July 10, 1866. To protect the Bozeman Trail, the army had established forts in Dakota Territory at Fort Reno (1865) and Fort Phil Kearny (1866). On August 12, 1866, the army established Fort C.F. Smith on the Big Horn River just inside the boundary of Montana Territory. Thus, by the narrow margin of one month, Camp Cooke became the first U.S. Army post in the Montana Territory.