FirstEnergy Corp. is an electric utility headquartered in Akron, Ohio. It was established when Ohio Edison merged with Centerior Energy in 1997. Its subsidiaries and affiliates are involved in the distribution, transmission, and generation of electricity, as well as energy management and other energy-related services. Its ten electric utility operating companies comprise one of the United States' largest investor-owned utilities, based on serving 6 million customers within a 65,000-square-mile (170,000 km²) area of Ohio, Pennsylvania, West Virginia, Virginia, Maryland, New Jersey, and New York. Its generation subsidiaries control more than 16,000 megawatts of capacity, and its distribution lines span over 194,000 miles. In 2018, FirstEnergy ranked 219 on the Fortune 500 list of the largest public corporations in the United States by revenue.