In the late 1870s, the War Department gradually moved the 9th and 10th cavalry north to forts in Wyoming, Montana, Utah, Nebraska and the Dakotas.
During that time, trouble broke out between Utes at the White River Agency in northwest Colorado and their naïve, overzealous agent, Nathan Meeker. In the fall of 1879, he pleaded for military help.
The Army sent three troops of the all-white Fifth Cavalry, a company of the Fourth Infantry and a 25-wagon supply train under Major Thomas Thornburgh from Fort Fred Steele, on the Union Pacific line near Rawlins, Wyoming Territory.
They confronted a band of Utes on the Milk River in Colorado, 15 miles east of the agency. Shots rang out, the soldiers circled the wagons and soon found themselves under heavy fire from warriors on bluffs above them. Thornburgh and 12 soldiers were killed within the first few minutes, and a long siege began.
Just 70 miles to the south, the veteran, 35-man Troop D of the 9th Cavalry under Capt. Francis Dodge learned of the siege from a courier. Dodge issued three days rations and extra ammunition. Traveling fast without wagons, they covered the 70 miles in 20 hours, arriving before daylight. The black 9th Cavalry troopers joined the trapped soldiers in their rifle pits behind breastworks of dead horses, enormously boosting morale.
“[W]e took those darkies in right along with us in the pits. We let ‘em sleep with us, and they took their knives and cut off slips of bacon from the same sides as we did,” one of the white troopers, apparently surprised at the weakening of his racial prejudice, later told the New York Herald.
The siege lasted four days. Sgt. Henry Johnson of the 9th later won the Medal of Honor for risking his life to bring water from the river to the thirsty soldiers, many of them wounded.
The site of the first Ft. McKinney, aka Cantonment Reno, is located in Johnson County, Wyoming. The site is in an open prairie environment on the Powder river, near the old Bozeman Trail crossing of the Powder River. No buildings or significant ruins remain from the active period in 1876-77. It may be visited year-round as weather permits.
The site of the second Fort McKinney on Clear Fork of the Powder, is commemorated by a highway interpretive sign located about two miles west of Buffalo, Wyoming on U.S Highway 16.