As heavy industry spread throughout the region, rivers such as the Hudson and Delaware were transformed into vital shipping lanes. Cities on waterways -- New York on the Hudson, Philadelphia on the Delaware, Baltimore on Chesapeake Bay -- grew dramatically. New York is still the nation's largest city, its financial hub, and its cultural center. But even today, the visitor who expects only factories and crowded cities is surprised. In the Mid-Atlantic, there are more wooded hills than factory chimneys, more fields than concrete roads, and more farmhouses than office buildings.

Source: http://usa.usembassy.de/travel-regions.htm