Disputes over grazing lands and water rights ignited violent conflicts across the American West in the late 1800s. Yet few proved as bloody as the 1892 Johnson County War, where large cattle barons launched an organized terror campaign against small ranchers for control of northern Wyoming’s fertile Powder River Valley.

A hired hit squad. A 70-person hit list (including local lawmen). A complicit governor. Witness-muzzling bribes. The cattle titans flexed their might in a multitude of ways to take down their small, homesteading competitors and to thwart justice from being served after their murderous rampage had roiled the northern plains.

While “range wars” were common in the West, “none could match the paramilitary scope, or the sheer harebrained nature, of the Johnson County War,” writes Christopher Knowlton, author of Cattle Kingdom: The Hidden History of the Cowboy West.

In the two decades following the Civil War, industrial meat-processing plants built to sustain the Union Army fed America’s growing appetite for beef. “Open range” ranching exploded in the West as millions of cows grazed at no cost on lush federal lands. The free grass fattened the herds—and the bank accounts of investors lured westward by publications such as the 1881 book The Beef Bonanza, or How to Get Rich on the Plains.

Bustling “cowtowns” sprouted across the prairie. In Cheyenne, Wyoming, cattle barons strolled beneath some of the country’s first electric streetlights. Inside the grand Cheyenne Club, members of the powerful Wyoming Stock Growers Association (WSGA) sipped fine wines and feasted on oysters.

In the latter part of the 1880s, however, the bovine bubble burst. Two drought-plagued summers seared the Great Plains before the brutal winter of 1886-1887 buried the frozen prairie under four feet of snow. The “Big Die-Up” killed millions of cattle, with some ranchers losing up to 80 percent of their steers.

Herds thinned along with the WSGA membership, which plummeted more than 80 percent between 1886 and 1890.“The trickle-down effect is that large operators start laying off cowboys, who don’t necessarily leave,” says Sylvia Bruner, executive director of the Jim Gatchell Memorial Museum in Buffalo, Wyoming. “They see the opportunity to start their own little operations and become competition for their previous employers.”

Adding to the cattle kings’ woes, the open range started to shutter. Under the 1862 Homestead Act, cowboys snapped up prime 160-acre parcels for $10 claims. “They’re required by the Homestead Act to fence their property, so they throw up fences that sometimes block the large cattle operators out of water access, causing even greater friction,” Bruner says.

Inside the Cheyenne Club’s smoke-filled parlors, WSGA members cursed the small ranchers occupying once-free grazing lands and accused them of “rustling,” stealing their cows and horses. Shockingly, the Wyoming cattle barons who once made a killing now plotted killings to revive their dwindling fortunes.

The Cheyenne Club’s rules strictly prohibited betting, fighting and card cheating—but said nothing about murder. In 1891, WSGA range detective Frank Canton organized a six-man assassination squad to target homesteaders in Johnson County, where he once served as sheriff. After hanging horse trader Tom Waggoner, the vigilantes stormed the cabin of outspoken cowboy Nate Champion, branded “king of the cattle thieves” by Cheyenne newspapers.

Awoken by a pair of attackers, Champion grabbed a Colt revolver from under his pillow and wounded his assailants, one mortally, while suffering only powder burns to his face. Three months later, authorities discovered the bullet-riddled bodies of two witnesses who had overheard an attacker’s confession.

When Canton’s vigilantes escaped prosecution, Cheyenne’s cattle kings bankrolled an even more ambitious killing spree in Johnson County. On April 5, 1892, a 52-man force boarded a private train leaving Cheyenne armed with dynamite, rifles and “enough ammunition to kill all the people in the state of Wyoming,” according to one witness. The “invaders,” as they became known in Johnson County, included 11 WSGA executive committee members and 25 gunmen recruited from Texas with the promise of $5 per day and a $50 bonus for every man killed.

Canton carried a hit list with 70 names that included Johnson County’s sheriff and deputy sheriff, three county commissioners and a newspaper editor. The planned decapitation of Johnson County’s government had the tacit backing of Wyoming Governor Amos Barber, who instructed the local militia to disregard any orders from the local sheriff.

The vigilantes’ first task was completing unfinished business—killing Champion. Before dawn on April 9, the invaders surrounded a small log bunkhouse at the KC Ranch, subdued two visitors fetching water and opened fire on Champion’s friend Nick Ray, who was also on the hit list, as he emerged from the doorway.

Champion dragged his mortally wounded friend inside the cabin where he waged a heroic last stand by keeping the attackers at bay the entire day. Taking cover in a pit burrowed into the dirt floor, the cowboy remarkably kept a running diary of events in a little red tally book. “There is bullets coming like hail,” he scribbled. “I don’t think they intend to let me get away this time.”

When Jack Flagg, another accused rustler on the hit list, came upon the shootout, he abandoned his wagon and galloped to the county seat of Buffalo to spread the alarm. The vigilantes loaded the abandoned cart with hay and freshly split pine, set it aflame and wheeled it against a cabin wall. “The house is all fired,” Champion wrote. “Goodbye, boys, if I never see you again.” Smoked out of the bunkhouse, Champion tucked the journal into his vest pocket and burst out the back door. His body was found with 28 bullet holes and a note that Canton pinned to his shirt: “Cattle Thieves Beware!”

Aware that Flagg had likely alerted Buffalo’s citizens, the invaders barricaded themselves in a barn at the TA Ranch, 14 miles to the south. A posse that eventually grew to several hundred men laid siege for three days.

When an invader who managed to escape the ranch informed Barber of the siege, Wyoming’s governor telegraphed the state’s two senators, who rushed to the White House. Aroused from bed, President Benjamin Harrison ordered the 6^th Calvary at nearby Fort McKinney to take the invaders into custody to prevent further bloodshed.

Once in custody, the vigilantes’ powerful connections stymied Jefferson County’s prosecutors. The cattle barons paid off witnesses, Barber prevented the defendants’ questioning and the cattlemen’s lead attorney, future Supreme Court Justice Willis Van Devanter, secured a change of venue to Cheyenne.

Once the Texas gunmen were released on bail, the cattle barons threw them a party at the Cheyenne Club—with Barber a guest of honor. The hired shots were given $750 and commemorative rings before departing Wyoming, never to return.

With the state refusing to bear any costs of feeding, housing and trying the prisoners, Jefferson County faced bankruptcy as jury selection dragged on for weeks. Unable to seat a jury after examining 1,064 eligible citizens, prosecutors eventually agreed to dismiss all charges.

Range war killings continued, only more covertly, in Johnson County and beyond as cattle barons deployed marksmen such as Tom Horn against their foes. The Johnson County War claimed between 20 and 40 lives by its conclusion in 1893, when the WSGA finally opened its membership to small cattlemen, ending one of the most vicious chapters in the history of the West.