The 20 Largest Strikes in American History

A labor strike is a voluntary suspension of work, collectively agreed upon and executed by workers in defense of common demands. Common causes of labor strikes throughout American history have included dismal and dangerous working conditions, low wages, hiring discrimination, long and strenuous hours, stretching the workforce too thin, and violating workers’ rights to unionize. Section 7 of the National Labor Relations Act states that “Employees shall have the right … to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection.” This chart from the Parker Waichman team reveals the largest worker strikes in American history by number of cumulative days off the job.

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What Was the Largest Strike in U.S. History?

The largest strike in American history in terms of cumulative hours off the job was the United Mine Workers of America Strike of 1946. Under the leadership of legendary union leader John L. Lewis and the United Mine Workers of America, around 400,000 workers went on strike to demand protection of health and welfare plans for both active workers and retirees. The strike lasted a staggering 250 days, from April 1 to Dec. 7, 1946. Eventually, President Harry S. Truman intervened and the U.S. government facilitated a compromise known as the Krug-Lewis Agreement (also known as the Promise of 1946). The agreement established the United Mine Workers of America Health and Retirement Funds. Retirement security was guaranteed for coal miners and their families to honor their service to the nation.

What Was the Deadliest Labor Dispute in U.S. History?

The deadliest labor dispute in U.S. history is known as the Battle of Blair Mountain. The conflict occurred in Logan County, West Virginia, from Aug. 25 to Sept. 2, 1921. Around 10,000 armed coal miners clashed with 3,000 law enforcers and strikebreakers. Since the founding of the United Mine Workers union in 1890, coal mine operators in Mingo County, West Virginia, refused to hire unionized workers, and any miners who joined would be promptly terminated and evicted (as most lived in company-sponsored towns). This caused tension to build, which led to arrests, acrimonious trials that gained national attention, and murders.

The conflict ignited when United Mine Workers leader Lewis sought to put an end to the resistance to unionization in that area. On Aug. 31, 1921, a violent battle erupted when armed union miners attempted to liberate the non-unionized miners and their families who had been living under martial law imposed by mine companies and the government. The miners waged war with armed forces marshaled by the county sheriff, coal company guards, and state police. There were around 100 victims in total, with 985 miners being arrested for murder, accessory to murder, conspiracy to commit murder, and treason. Due in part to public sympathy for the miners, most were acquitted or had short sentences.

Are Unions Legal in the United States?

It depends. Private-sector worker unions are governed by the National Labor Relations Act. Public-sector unions are regulated by labor laws and labor boards across all states. Northern states generally model their labor laws after the NLRA, but in other states, public workers have no right to establish a union to protect themselves from unethical employers. Around 40% of public employees do not have the right to create or join a union.