On the shoulder of a lonely stretch of highway miles into the hills, a sign stands in the weeds. “Battle of Blair Mt.,” it says, informing the tumbledown cinder block building across the road that here, 100 years ago, was the largest armed labor uprising in U.S. history.

In late August 1921, thousands of rifle-bearing coal miners marched to this thickly wooded ridge in southern West Virginia, a campaign that was ignited by the daylight assassinations of union sympathizers but had been building for years in the oppressive despair of the coal fields. The miners’ army was met at Blair Mountain by thousands of men who volunteered to fight with the Logan County sheriff, who was in the pay of the coal companies. Over 12 miles and five days, the sheriff’s men fought the miners, strafing the hillsides with machine-gun fire and dropping homemade bombs from planes. There were at least 16 confirmed deaths in the battle, though no one knows exactly how many were killed before the US Army marched in to put a stop to the fighting.

The roadside marker and the spent shell casings found in the hillsides are the only reminders at Blair Mountain that this took place.

The country has begun wrestling in recent years with its buried trauma, memorializing vile and suppressed histories like the Tulsa Race Massacre. The Battle of Blair Mountain, the culmination of a series of violent conflicts known as the Mine Wars, would also seem to be a candidate for such exhumation.

The army of miners that came to Blair Mountain was made up of Black and white people, new immigrants and people with deep roots in Appalachia. They did perilous work under conditions close to indentured servitude: They were kept in line by armed guards and paid only in company scrip, with their pay docked for the costs of housing, medical care and the tools they used in the mines. These conditions eventually erupted in the largest insurrection since the Civil War.

But while there are commemorations this weekend in West Virginia, including talks, rallies and re-enactments, a century of silence enforced by power and fear has left the battle nearly forgotten elsewhere.

“It is one of the most amazing confrontations between workers and bosses ever in this country and no one knows about it,” said Cecil Roberts, the president of the United Mine Workers of America and a great-nephew of Bill Blizzard, who led the miners’ army in 1921. “It seems to be almost impossible unless there’s a concerted effort for people not to know about it.”

The Mine Wars era was bloody, with at least 100 deaths in shootouts and violent crackdowns. For most of the 20th century, silence about it served mutual interests. The participants kept quiet out of self-protection and solidarity. Mr. Blizzard was charged with treason and murder, though he was acquitted, and some of the most prominent labor leaders faced permanent ostracism. Frank Keeney, who roused thousands to fight as head of the U.M.W.A. local, spent the latter part of his life as a parking lot attendant.

Mr. Keeney’s great-grandson, Charles B. Keeney, a history professor at Southern West Virginia Community and Technical College, had trouble getting his own family to talk about the uprising. Instead, he learned about it from stray remarks at family cookouts and from older strangers, who told him star-struck tales after approaching him when they learned of his family connection.

But it was primarily the coal industry and its supporters in state government, Mr. Keeney and other historians said, who tried to smother any public discussion of the history. State officials demanded that any mention of Blair Mountain be stripped from federal oral histories. A 1931 state law regulated the “study of social problems” and for decades, the Mine Wars were left entirely out of school history textbooks. Today, the battlefield is owned in large part by coal operators, who until recently planned to strip mine Blair Mountain itself.