Fort Reno (also known as Fort Connor or Old Fort Reno) was a wooden fort constructed in 1865 by the United States Army on the Great Plains frontier in the Dakota Territory in present-day Johnson County, Wyoming. It served to protect travellers on the Bozeman Trail from warring Native American tribes.
Following the American Civil War, a large number of settlers headed west to seek new opportunities and land. With the discovery of gold in the Black Hills region of what is today Montana, large numbers of miners, adventurers, and settlers flocked to the area, but lacked a direct route to the gold fields. Soon, the Bozeman Trail was constructed through the middle of a region considered sacred by the Lakota Sioux, who began to attack travellers along the trail. Concerned, the Army constructed a series of forts and outposts in 1865–66 to house garrisons to deter the Indians.
One such fort was established on August 14, 1865, on a high plateau on the banks of the Powder River near the mouth of Dry Fork. It was originally named "Fort Connor" for Brig. Gen. Patrick Connor, whose men of the 6th Michigan Cavalry constructed the fort as a supply depot during the Powder River Expeditions of that summer. On November 11, 1865, the post was renamed "Fort Reno" in honor of Maj. Gen. Jesse L. Reno, who had been killed in the American Civil War at the Battle of South Mountain.
Fort Reno was crudely built with a quartermaster's and commissary warehouse and stables surrounded by a 120 square foot stockade of 8-10" diameter cottonwood logs. The rough logs were set four feet deep in a trench, leaving a wall about eight feet high. During the fall of 1865, workers constructed other buildings outside of the stockade, including two barracks, two officers' quarters, hospital, shops, teamsters' quarters, and two sutler's buildings. All of the buildings had sod-covered roofs and dirt floors. In August, Companies C and D of the 5th U. S. Volunteers (a command of former Confederate prisoners of war who had taken the oath of allegiance), and Company A, Omaha Scouts (members of the Winnebago tribe), relieved the Michigan cavalry. Under the command of Capt. George M. Bailey, they garrisoned the isolated fort during the harsh winter of 1865–66.
During Red Cloud's War the following summer, Col. Henry B. Carrington of the 18th U. S. Infantry led a force of 700 men into the Powder River country to begin construction of two other new posts farther to the north. They reached Fort Reno on June 28, 1866, and stayed two weeks. When he left on July 9, Carrington left behind two companies to replace the existing volunteer garrison, which mustered out of the service and departed home "without a single regret." The newly arrived Regular Army soldiers constructed a log stockade around the unprotected garrison buildings, complete with log bastions on the northwest and southeast corners. They also built a sturdy adobe commander's quarters. In 1867, the post was renovated and expanded. The garrison (whose number ranged from 125 to a high of 300 soldiers) endured the routines of camp life and the harsh winters and hot summers, occasionally skirmishing with hostile Indians and keeping the southern end of the Bozeman Trail open and passable.
The 1868 Treaty of Fort Laramie ended Red Cloud's War and essentially ceded much of their old hunting grounds to the Lakota. Along with Forts C.F. Smith and Phil Kearny, Fort Reno was abandoned as a condition of the agreement. Shortly after the military left, the entire post was destroyed by fire, possibly ignited by Cheyenne warriors. Gen. George Crook's troops briefly visited Fort Reno in March 1876, but found that all that was left were some adobe walls and building debris. Nevertheless, he used the site as a supply base.
Bodies left in the post cemetery were later reinterred and placed at the Custer Battlefield National Cemetery during the 1880s. The grounds that comprised the fort site have generally returned to a natural prairie sod cover.
The site, approximately 12 miles northeast of Sussex, Wyoming, was listed on the National Register of Historic Places on March 28, 1970. There is a large stone monument and several interpretive signs marking the site.