WikipediaThe Harlan County War, or Bloody Harlan, was a series of coal mining-related skirmishes, executions, bombings, and strikes (both attempted and realized) that took place in Harlan County, Kentucky, during the 1930s. The incidents involved coal miners and union organizers on one side, and coal firms and law enforcement officials on the other. The question at hand: the rights of Harlan County coal miners to organize their workplaces and better their wages and working conditions. It was a nearly decade-long conflict, lasting from 1931 to 1939. Before its conclusion, an indeterminate number of miners, deputies, and bosses would be killed, state and federal troops would occupy the county more than half a dozen times, two acclaimed folk singers would emerge, union membership would oscillate wildly, and workers in the nation's most anti-labor coal county would ultimately be represented by a union.
https://en.wikipedia.org/wiki/Harlan_County_War