On July 6, 1892, 300 Pinkerton agents, a private security force hired by Henry Clay Frick, attempt to disperse 5,000 locked out Homestead steelworkers by landing at the pump house in barges pushed by tugboats up the Monongahela River. They were defeated in the Battle of Homestead, and surrendered to the striking steelworkers. Unrest continued for days until 4,000 state militiamen were called in to retake the plant. The militia, combined with nonunion strikebreakers, eventually broke the Amalgamated Association of Iron and Steel Workers union.
The Disaffected: Britain's Occupation of Philadelphia During the American Revolution, PA Books
Pittsburgh and the Great Steel Strike of 1919, PA Books
George Gordon Meade, Civil War Institute