The Potomac River flows into the Chesapeake Bay, located along the mid-Atlantic coast of the United States (USA). The river is approximately 383 statute miles (665 km) long, with a drainage area of about 14,700 square miles (38,000 km²). In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the USA and the 21st largest in the USA. Over 5 million people live within the Potomac watershed, where precipitation provides the equivalent of over 8 m³ (more than 2,100 US gallons) of water per person per year.