The mainstem Delaware River, the longest un-dammed river east of the Mississippi, extends 330 miles from the confluence of its East and West branches near Hancock, New York, to the mouth of the Delaware Bay.

Approximately five percent of the nation's population relies on the basin's waters for drinking and industrial use, and the bay is only a gas tank away for about 23 percent of the people living in the United States. Yet, the watershed drains only 0.4 percent of the continental U.S. land area.

In all, the basin comprises 13,539 square miles, including portions of Delaware, New Jersey, New York, and Pennsylvania.