The Civil War hit the Ozarks in southern Missouri and northern Arkansas especially hard. While the region was underpopulated, that made it a good home for guerrillas from both sides as well as simple bandits. Taney County in Missouri went from a prewar population of 3,500 to fewer than 1,000 by war's end.
Peace didn't come quickly to the Ozarks. When Confederate veterans returned home, many found their land occupied by Union men, confiscated for failure to pay taxes during the war. They couldn’t even vote thanks to a new state constitution that disenfranchised anyone who had supported the rebellion.
The local government became dominated by Union men, many of them newcomers who arrived to snap up cheap land. While some ex-Confederates did manage to get farms again, they had become an underclass. Some turned to lawlessness, usually targeting the wealthier Unionists.
The violence came to a head in the 1880s when a Union veteran named Nat Kinney formed the Baldknobbers, a vigilante group named after their practice of meeting on bald knobs, treeless hills where they could spot anyone coming to spy on their meetings. The Baldknobbers soon took to terrorizing the lawless element at night, wearing masks and whipping people. They soon graduated to lynching. In defense, the former rebels formed the Anti-Baldknobbers.
Soon the Civil War was being reenacted in the Ozarks. Many Baldknobbers were newcomers, Republicans, and ex-Union soldiers. Only a few kept farms, the main occupation of the general population, instead working in county government, law, or owning their own businesses. They looked on the native hill men as backward. The Anti-Baldknnobbers tended to be ex-Confederates and longtime residents, and most farmed for a living.
It's unclear how many died in the fighting. Estimates range from a dozen to more than thirty, with countless more beaten and driven from their land.
The lynchings, night riding, and shootouts were finally stamped out by Governor Marmaduke who, strangely enough, was a former Confederate general who came into power after the restrictions on ex-rebels holding public office was lifted. He didn't care who had fought for whom, he just wanted the killing to stop.
You can read more about the Baldknobbers in my book
Outlaw Tales of Missouri.
This
Wikimedia Commons photo is from the 1919 film,
The Shepherd of the Hills and accurately depicts surviving Baldknobber masks.