The Chesapeake Bay ( /ˈtʃɛsəpiːk/ CHESS-ə-peek) is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers 64,299 square miles (166,534 km²) in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia. More than 150 rivers and streams drain into the bay.