Chicago is a major commercial, industrial and cultural center in the United States. It is renowned for its transport hub, with the highest number of air departures and rail traffic in the country. The city is home to more than 30 Fortune 500 companies in a variety of industries, as well as small businesses and manufacturers. The suburbs have outgrown many farming communities and old towns, such as Elgin and Aurora. Naperville, located between the area's bypasses, has become a major commercial hub. Joliet is an older industrial and transportation hub on the southwest side. Location relative to major transportation routes is the most important factor in Chicago. Traffic along arteries and ring roads can be heavy due to the highland population. Downtown Chicago and nearby neighborhoods have become so livable that rush hour traffic affects people leaving the city. Highland is a unit of Indiana Dunes National Lakeshore managed by the Indiana Department of Natural Resources.
