Molly Maguires (məgwī´ərz), secret organization of Irish-Americans in the coal-mining districts of Pennsylvania. Its name came from a woman who led an extralegal, antilandlord organization in Ireland during the 1840s, and its membership was drawn from the Ancient Order of Hibernians, an Irish-American fraternal society. For several years, especially from c.1865 to 1875, the Molly Maguires dominated the mining industry of E Pennsylvania. The movement arose to combat the oppressive industrial and living conditions. Since the police and the forces for law and order were entirely controlled by the mine owners, the Molly Maguires often resorted to intimidating or murdering the police. Agents and superintendents were continually molested. The Mollies reached the height of their power c.1875, when they managed to organize a union in a region otherwise virtually unorganized and to call a strike. Franklin Gowen, president of the Reading RR, which had extensive mining interests, hired the Pinkerton agency to infiltrate the union, and the power of the Molly Maguires was finally broken by the spying activities of James McParlan, a Pinkerton detective. Ten of the Molly Maguires were hanged. McParlan's secret reports were released for study in 1947.