Definition of Molly maguire

The Molly Maguires was a 19th century secret society of mainly Irish-American coal miners. Many historians believe the "Mollies" were present in the anthracite coal fields of Pennsylvania in the United States between the time of the American Civil War until a series of sensational arrests and trials from 1876-78. The Molly Maguires were accused of kidnapping and other crimes, largely because of the allegations of one powerful industrialist (Franklin B. Gowen), and the testimony of one Pinkerton detective (James McParland). Fellow prisoners testified against the defendants, who were arrested by the Coal and Iron Police, who served Gowen, who acted as prosecutor in some of the trials.