The year 1876 saw intensive Indian campaigns extended by the army across the whole Northern Plains region. Troops came from posts in the Department of the Platte and swept most of the hostile Sioux and Cheyenne Indians out of present Wyoming, and participated in major engagements in southern Montana as well. By the time the campaigns drew to a seasonal halt in January of 1877, plans were under way for a series of military posts to provide bases from which the troops could prevent the Indians reoccupying their old hunting grounds. One of these posts was located on the west bank of Powder River, opposite the mouth of Dry Fork, and called at first, ''Cantonment Reno.'' Soon renamed ''Fort McKinney'' in honor of Lt. J. A. McKinney (killed in the battle with the Cheyenne on Red Fork of Powder River, November 25, 1876), this post was occupied through the spring of 1878. After considerable study, it was abandoned because of poor water, wood and forage supplies nearby, and the name transferred along with the troops to a new site on a broad terrace above Clear Fork of Powder River where that stream exits form the Big Horn Mountains. The new site was occupied and construction activities under way in July of 1878. The post at peak of development consisted of barracks for seven companies of troops, at least 14 structures for officer quarters, stables, warehouses, laundress quarters, a hospital, bakery, offices, and auxiliary structures.

Troops from Fort McKinney and neighboring posts were responsible for keeping the lately-hostile Sioux and Cheyenne from reverting to their old way of life in a vast region. They were supposed to keep the friendly Crows and Shoshoni from resuming their intermittent warfare with tribal enemies, and to prevent the Arapahoe from becoming embroiled with settlers and other tribes while officials pondered their disposition. They did this work well. They guarded communication lines that included the ''Rock Creek Stage Line'' which provided mail, passenger and express service from Rock Creek on the UPRR to Terry's Landing on the Yellowstone. They built and maintained the first telegraph line into the Powder River country.

Located in north central Wyoming 20 miles northwest of Buffalo nestled into the foothills of the Big Horn Mountains, the HF Bar Ranch is a working cattle/dude ranch complex consisting of 36 buildings predominately of rustic frame and log construction built primarily between 1898 and 1921. Wyoming state senator and U. S. congressman, Frank Horton, with the financial backing and capital of his brother-in-law and sister-in-law, Chicago investment banker, Warren Gorrell and his wife Demia Gorrell, purchased the 1890s homestead in 1911. Warren and Demia Gorrell and their four children spent most of their summers at the HF Bar Ranch between 1911 and 1929. While the Gorrells continued to reside principally in Chicago, the Horton family lived year-round in Wyoming, as Frank Horton managed the day-to-day operations of the Ranch. Throughout this period, Warren and Demia Gorrell continued as the major stockholders, financial backers and supporters of the HF Bar. With the Stock Market Crash of 1929, Warren and Demia Gorrell sold their shares in the HF Bar Ranch, and associates of Frank Horton purchased them. The HF Bar Ranch is significant as an intact example of a working dude ranch in continuous use for nearly 100 years. It is one of the best remaining representatives of similar operations which flourished during peak years of the cattle ranching frontier, then turned to dude ranching in the face of economic difficulties. The ranch is associated with the state and locally significant tourist industry which brought wealthy easterners and Europeans to the West. Their influence subsequently enriched the social, intellectual, cultural and economic climate of the entire region.