Range wars were infamous armed conflicts that took place in the "open range" of the American frontier. The subject of these conflicts was the control of lands freely used for farming and cattle grazing which gave the conflict its name. Range wars became more common by the end of the American Civil War, and numerous conflicts were fought such as the Pleasant Valley War, Mason County War, Johnson County War, Colorado Range War, Fence Cutting War, Colfax County War, Castaic Range War, Barber–Mizell feud, San Elizario Salt War and others. During a range war in Montana, a vigilante group called Stuart's Stranglers, which were made up of cattlemen and cowboys, killed up to 20 criminals and range squatters in 1884 alone. In Nebraska, stock grower Isom Olive led a range war in 1878 that killed a number of homesteaders from lynchings and shootouts before eventually leading to his own murder. Another infamous type of open range conflict were the Sheep Wars, which were fought between sheep ranchers and cattle ranchers over grazing rights and mainly occurred in Texas, Arizona and the border region of Wyoming and Colorado. In most cases, formal military involvement were used to quickly put an end to these conflicts. Other conflicts over land and territory were also fought such as the Regulator–Moderator War, Cortina Troubles, Las Cuevas War and the Bandit War.