Foresight Energy LP engages in the development, mining, transportation, and sale of thermal coal primarily in the eastern United States and internationally. It operates four underground mining complexes, including Williamson, Sugar Camp, Hillsboro, and Macoupin in the Illinois Basin. It controls approximately 3 billion tons of coal reserves in the Illinois Basin. The company sells its coal to electric utility and industrial companies. The company was formerly known as Foresight Energy Partners LP and changed its name to Foresight Energy LP in April 2014. The company was founded in 2006 and is headquartered in St. Louis, Missouri. As of April 16, 2015, Foresight Energy, LP operates as a subsidiary of Murray Energy Corporation.