The unrest among workers in Pittsburgh was triggered by violent incidents involving the Maryland militia and Baltimore and Ohio Railroad (B&O) workers who had rioted after a series of wage cuts and layoffs. The B&O workers’ protest turned deadly when militia troops intervened, resulting in the deaths of nine workers. News of these events quickly spread, igniting a wave of sympathy strikes among railroad workers in various cities, including Pittsburgh. On July 21, workers halted work and protested, expressing solidarity with their fallen comrades in Maryland.

The response from Pittsburgh's state militia was swift and brutal. Armed troops were deployed to dismantle the strike, clashing with striking workers who sought to defend their right to protest and organize for better conditions. The situation grew increasingly violent, as confrontations led to several injuries and arrests. The strike not only reflected the dire economic circumstances of the working class but also highlighted the rising tensions between labor and the state, setting the stage for ongoing labor struggles in the late 19th century.

This event was part of a broader wave of strikes and labor unrest, known historically as the Great Railroad Strike of 1877, which affected the entire nation. Workers were demanding better wages, safer working conditions, and the right to unionize. The violent crackdown by the militia in Pittsburgh exemplified how authorities viewed labor organization as a threat, often responding with force rather than negotiation. This direct confrontation between workers and military forces would mark a pivotal moment in labor history, paving the way for future labor movements and reforms.