The Mid Atlantic water resource region is one of 21 major geographic areas, or regions, in the first level of classification used by the United States Geological Survey to divide and sub-divide the United States into successively smaller hydrologic units. These geographic areas contain either the drainage area of a major river, or the combined drainage areas of a series of rivers.[1][2]
The Mid Atlantic region, which is listed with a 2-digit hydrologic unit code (HUC) of 02, has an approximate size of 106,334 square miles (275,400 square kilometers), and consists of 8 subregions, which are listed with the 4-digit HUCs 0201 through 0208.
This region includes the drainage within the United States that ultimately discharges into: (a) the Atlantic Ocean within and between the states of New York and Virginia; (b) Long Island Sound south of the New York-Connecticut State Line; and (c) the Riviere Richelieu, a tributary of the St. Lawrence River. It includes all of Delaware and New Jersey and the District of Columbia, and parts of Connecticut, Maryland, Massachusetts, New York, Pennsylvania, Vermont, Virginia, and West Virginia.[3]