Illinois is a state in the Midwestern region of the United States. It is the 6th-most populous U.S. state and 25th-largest state in terms of land area, and is often noted as a microcosm of the entire United States. With Chicago in the northeast, small industrial cities and great agricultural productivity in northern and central Illinois, and natural resources such as coal, timber, and petroleum in the south, Illinois has a diverse economic base, and is a major transportation hub. The Port of Chicago connects the state to other global ports around the world from the Great Lakes, via the Saint Lawrence Seaway, to the Atlantic Ocean; as well as the Great Lakes to the Mississippi River, via the Illinois Waterway on the Illinois River. The Mississippi River, the Ohio River, and the Wabash River form parts of the boundaries of Illinois. For decades, Chicago's O'Hare International Airport has been ranked as one of the world's busiest airports. Illinois has long had a reputation as a bellwether both in social and cultural terms and politics.