In the early days in Wyoming most of the land was in the public domain, open both to stockraising as open range and to homesteading. Large numbers of cattle were turned loose on the open range by large ranches, sometimes financed by English and other investors. In the spring a roundup was held and the cows and the calves belonging to each ranch were separated and the calves branded. Before the roundup, sometimes calves, especially orphan or stray calves, were surreptitiously branded, and thus taken. The large ranches, concerned about this practice, forbade their employees from owning cattle and aggressively defended against rustling.
Attempts were made to exclude the smaller ranchers from participation in the annual roundup and apparently agents of the larger ranches killed several alleged rustlers. The large ranches were organized as the Wyoming Stock Growers Association and gathered socially as the Cheyenne Club in Cheyenne, Wyoming. Hiring guns from Texas, an expedition of 50 men was organized which proceeded by train from Cheyenne to Casper, Wyoming, then toward Johnson County intending to eliminate alleged rustlers and also apparently to replace the government in Johnson County. To prevent an alarm the telegraph lines out of Buffalo were cut. The expedition was accompanied by two newspaper reporters whose lurid accounts later appeared in the eastern newspapers.
The first target was Nate Champion at the KC Ranch, a small rancher who was active in the efforts of small ranchers to organize a competing roundup. Four men were at the KC; two were captured as they emerged from the cabin; one was shot and died a few hours later; the fourth, Nate Champion was besieged. Two passers-by noticed the ruckus and rode to Buffalo where the sheriff of Johnson County raised a posse of 200 men and set out for the KC. Back at the ranch the cabin was set on fire and when Nate Champion emerged he was gunned down.
The following day the posse led by the sheriff besieged the invading force at the TA Ranch on Crazy Woman Creek. After two days one of the invaders escaped and was able to contact the acting Governor of Wyoming. Frantic efforts to save the besieged invaders ensued and telegraphs to Washington resulted in intervention by the President of the United States, Benjamin Harrison. The Sixth Cavalry from Fort McKinney was ordered to proceed to the TA ranch and take custody of the invaders and save them from the posse.
In the end the invaders went free after the court venue was changed and the charges dropped. There was a stink and for a time Wyoming went Democratic.
The Johnson County War with its overtones of class war, English colonialism and intervention of the President of the United States to save the lives of a bunch of hired killers, coupled with them all going free, does not fit in well with the American myth of the west, being on the verge of damned knowledge. The film, The Johnson County War which premiered August 24, 2002 on the Hallmark Channel is based on the incident.