The Westmoreland County coal strike of 1910–1911, or the Westmoreland coal miners' strike, was a strike by coal miners represented by the United Mine Workers of America. The strike is also known as the Slovak Strike because about 70 percent of the miners were Slovak immigrants. It began in Westmoreland County, Pennsylvania, on March 9, 1910, and ended on July 1, 1911. At its height, the strike encompassed 65 mines and 15,000 coal miners. Sixteen people were killed during the strike, nearly all of them striking miners or members of their families. The strike ended in defeat for the union.