FirstEnergy Corporation is a diversified energy company headquartered in Akron, Ohio. Its subsidiaries and affiliates are involved in the generation, transmission, and distribution of electricity, as well as energy management and other energy-related services. Its ten electric utility operating companies comprise the United States' largest investor-owned utility, based on serving 6 million customers within a 67,000-square-mile (170,000 km) area of Ohio, Pennsylvania, West Virginia, Virginia, Maryland, New Jersey and New York. Its generation subsidiaries control more than 23,000 megawatts of capacity, and its distribution lines span over 194,000 miles. In 2013, FirstEnergy ranked 181 on the Fortune 500 list of the largest public corporations in America.