In all of our country’s history, no single labor strike has engulfed more lives than the Battle of Blair Mountain: the largest labor skirmish ever in the US and one of the bloodiest battles fought on American soil since the Civil War. It began in 1921, as tensions between coal industry workers and overseers boiled to an extreme, and culminated in a gunfire assault that swallowed Logan County, West Virginia, leaving as many as 100 dead, and nearly 1000 arrested.

The battle was preceded by decades of worker abuse by coal companies. Miners in Mingo, Logan and McDowell Counties slaved in unsafe conditions using leased tools. For their efforts, they were paid in “scrips,” a currency only redeemable at company stores. Unions such as the  United Miners Workers Association (UMW) attempted to establish a foothold in the area, but membership was sparse, as intimidations and violence cowed those who tried organizing back into subservience. Another common manipulation involved having workers sign “yellow dog contracts,” which forbade them from joining unions under threat of eviction from their company-owned dwellings.

To enforce their rule, company management employed the Baldwin Felts Detective Agency, a private firm. The soft moniker “detective agency” obscures the fact that Baldwin Felts agents often swept through strike camps armed with tommy guns, high-powered ordnance, and an armored, gatling-mounted train which miners called the “death special.” On May 19, 1920, an argument between Baldwin Felts agents attempting to evict miners in Matewan, WV, and a local posse led by sheriff Sid Hatfield overheated into a ten-man massacre that left dead the mayor of Matewan, two miners, and seven Baldwin Felts agents.

UMW membership soared following the “Matewan Massacre.” In response, the companies brought in fresh, non-union workers, and met with equal resistance any attempts at a forceful union takeover. Fighting was initially confined to isolated guerilla spats, but that changed when Sid Hatfield—who had become a leader and a symbol of the miners’ movement—was shot dead by Baldwin Felts agents at the McDowell County courthouse. News of Hatfield’s demise spurred thousands of union faithful into action. Many were fighting men, veterans of World War I who felt compelled to once again take up their Springfield rifles and shotguns.

Under the direction of UMW heads Frank Keeney and Fred Mooney, a makeshift army of 10,000 plus miners gathered. Their goal was to sweep through Logan County and march on Mingo, where many miners were being held under martial law. In their way stood a militia of 3,000 citizens, Baldwin Felts Agents and police. The counterforce was commanded by Don Chafin, a local sheriff who received financial backing from the Logan County Coal Operators Association.

For five days following August 31, machine gun fire rang throughout Blair Mountain. When the fighting grew fierce, Chafin called in a trio of private planes to drop bombs filled with shrapnel and tear gas into miner emplacements. The battle ended when miners learned that President Warren Harding had mobilized 2,100 federal troops to bolster the anti-union force. Most miners fled before the troops arrived, and the 985 who remained surrendered and were arrested. The battle’s death toll is estimated at anywhere from 20 to 100, with the miners suffering the majority of casualties. Of those arrested, some were acquitted, while others were imprisoned for several years, with the last being released on parole in 1925.

The Battle of Blair Mountain was an immediate victory for coal operators, as UMW membership declined in the aftermath from 50,000 to 10,000. In terms of publicity, however, coal companies took a massive hit. Workers’ slavelike conditions were exposed, and cited as evidence to win greater political victories for organized labor, including the National Industrial Recovery Act (which gave the president the authority to regulate wages and prices) and the Wagner Act (which created the National Labor Relations Board and established the right of workers to form and join unions as well as engage in collective bargaining and collective actions, such as strikes).