The Banditti of the Prairie, also known as The Banditti, Prairie Pirates, Prairie Bandits, and Pirates of the Prairie, in the U.S. states of Illinois, Indiana, and Ohio, and the Territory of Iowa, were a group of loose-knit outlaw gangs, during the early to mid-19th century. Though bands of roving criminals were common in many parts of Illinois, the counties of Lee, DeKalb, Ogle, and Winnebago were especially plagued by them. The new crime wave in the region of the frontier Midwest may have occurred following the crackdown on southern outlaws by the rising vigilante-regulator movement and the breakup of the criminal syndicate of John A. Murrell and his gang, the "Mystic Clan" in the Southern United States. In 1841, the escalating pattern of house burglary, horse and cattle theft, stagecoach and highway robbery, counterfeiting, and murder associated with the Banditti had come to a head in Ogle County. As the crimes continued, local citizens formed bands of vigilantes known as Regulators. A clash between the Banditti and the Regulators in Ogle County near Oregon, Illinois, resulted in the outlaws' demise and decreased Banditti activity and violent crime within the county.