Inlet of the Atlantic Ocean, eastern U.S. With its lower section in Virginia and its upper section in Maryland, it is 193 mi (311 km) long and 3–25 mi (5–40 km) wide and has an area of about 3,230 sq mi (8,365 sq km).
It receives many rivers, including the Potomac , and James . Jamestown , the area's first European settlement, was founded in 1607; a year later, Capt. {{link=Smith, John">John Smith explored and mapped the bay. The bay's waters had supported vast amounts of marine life, but by the 1970s development of the surrounding area led to alarming pollution of the bay; fishing dropped off sharply. Efforts have since been made to reverse the damage.