Illinois is a state in the Midwestern United States. The Great Lakes are to its northeast, the Mississippi River to its west, and the Ohio River to its south. Its largest metropolitan areas are Chicago and the Metro East region of Greater St. Louis. Other metropolitan areas include Peoria and Rockford, as well as Springfield, its capital, and Champaign-Urbana, home to the main campus of the state's flagship university. Of the fifty U.S. states, Illinois has the fifth-largest gross domestic product , the sixth-largest population, and the 25th-largest land area.