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Facts & Figures

Learn all about the Chesapeake Bay's geography, watershed, flora and fauna with this list of interesting facts and figures.

Bay Geography

  • The Chesapeake Bay is an estuary: a body of water where fresh and salt water mix. It is the largest of more than 100 estuaries in the United States and third largest in the world.
  • The Bay itself is about 200 miles long, stretching from Havre de Grace, Maryland, to Virginia Beach, Virginia.
  • The Bay’s width ranges from four miles near Aberdeen, Maryland, to 30 miles near cape Charles, Virginia.
  • The mouth of the Chesapeake Bay is about 12 miles wide between its northern point near Cape Charles, Virginia, and its southern point close to Cape Henry, Virginia.
  • The surface area of the Bay and its tidal tributaries is approximately 4,480 square miles.
  • Two of the United States’ five major North Atlantic ports—Baltimore and Hampton Roads—are on the Bay.
  • The Bay and its tidal tributaries have 11,684 miles of shoreline—more than the entire U.S. west coast.
  • The Chesapeake Bay was formed about 10,000 years ago when glaciers melted and flooded the Susquehanna River valley.
  • The Bay is surprisingly shallow. Its average depth, including all tidal tributaries, is about 21 feet. A person who is six feet tall could wade through more than 700,000 acres of the Bay and never get his or her hat wet.
  • A few deep troughs run along much of the Bay’s length and are believed to be remnants of the ancient Susquehanna River.
  • The deepest part of the Bay, located southeast of Annapolis near Bloody Point, is called “The Hole” and is 174 feet deep.
  • Major rivers emptying into the Bay include the James, York, Rappahannock, Potomac, Patuxent, Patapsco and Susquehanna from the west and the Pocomoke, Wicomico, Nanticoke, Choptank and Chester from the east.


  • A watershed is an area of land that drains into a particular river, lake, bay or other body of water.
  • The Chesapeake Bay Watershed stretches approximately 524 miles from Cooperstown, New York to Norfolk, Virginia. It includes parts of six states—Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia—and the entire District of Columbia.
  • The area of the watershed is about 64,000 square miles.
  • The Chesapeake Bay’s land-to-water ratio is 14:1: the largest of any coastal water body in the world. This is why our actions on land have such a big impact on the Bay’s health.
  • The Chesapeake Bay watershed is home to almost 18 million people. Ten million of them live along or near the Bay’s shores. About 150,000 new people move into the Bay watershed each year.
  • There are nearly 1,800 local governments in the Bay watershed, including towns, cities, counties and townships.
  • The Chesapeake Bay watershed contains three distinct geologic regions: the Atlantic coastal plain, the Piedmont plateau and the Appalachian province.
  • Approximately eight million acres of land in the Bay watershed are permanently protected from development.
  • The Chesapeake Bay was the first estuary in the nation to be targeted for restoration as an integrated watershed and ecosystem.


  • The Chesapeake Bay holds more than 18 trillion gallons of water.
  • Approximately 51 billion gallons of water flow into the Bay each day from its freshwater tributaries.
  • The Bay receives about half its water volume from the Atlantic Ocean in the form of saltwater. The other half (freshwater) drains into the Bay from the enormous 64,000-square-mile watershed.
  • The Susquehanna River is the Bay’s largest tributary, and contributes about half of the Bay’s freshwater (about 19 million gallons per minute).
  • Collectively, the Chesapeake’s three largest rivers—the Susquehanna, Potomac and James Rivers—provide more than 80 percent of the fresh water to the Bay.
  • The Chesapeake Bay watershed has 150 major rivers and streams, but contains more than 100,000 smaller tributaries.
  • There are more than 700 public access points on the Chesapeake Bay and its tributaries.

Flora and Fauna

  • The Bay supports more than 3,600 species of plants and animals, including 348 species of finfish, 173 species of shellfish, over 2,700 plant species and more than 16 species of underwater grasses.
  • The Chesapeake region is home to at least 29 species of waterfowl.
  • During the winter, the Bay supports 87 species of waterbirds. Of these wintering waterbirds, 14 species rely on the Bay to serve as habitat for more than ten percent of their continental populations.
  • Nearly one million waterfowl winter on the Bay–approximately one-third of the Atlantic coast’s migratory population. The birds stop to feed and rest on the Bay during their annual migration along the Atlantic Migratory Bird Flyway.
  • More than 500,000 Canada geese winter in and near the Bay.
  • The Bay produces about 500 million pounds of seafood per year.
  • Nearly 80,000 acres of underwater grasses grow in the shallows of the Chesapeake Bay and its tributaries. Young and molting blue crabs rely on underwater grass beds for protection from predators.
  • Approximately 284,000 acres of tidal wetlands grow the Chesapeake Bay region. Wetlands provide critical habitat for fish, birds, crabs and many other species.
  • Forests and trees help filter and protect the drinking water of 75 percent of watershed residents.
  • Forests cover 55 percent of the Chesapeake Bay watershed. Between 1990 and 2005, the watershed lost an estimated 100 acres of forest land each day. While this rate fell in 2006 to an estimated 70 acres per day, this rate is still unsustainable.
  • Seventy to ninety percent of all striped bass, known locally as rockfish, were spawned in the Bay.
  • Sixty percent of Chesapeake forests have been divided into disconnected fragments by roads, homes and other gaps that are too wide or dangerous for wildlife to cross.
  • Since 1990, commercial watermen have harvested more than 1.6 billion pounds of blue crabs from the Bay. Data show commercial harvest has experienced a steady decline, and in 2014 hit the lowest level recorded in 25 years: 35 million pounds.
  • Just like those on land, animals in the Chesapeake Bay need oxygen to survive. Oxygen is present underwater in dissolved form, and in order to thrive, animals like blue crabs need dissolved oxygen concentrations of three milligrams per liter.


  • The word Chesepiooc is an Algonquian word referring to a village "at a big river." In 2005, Algonquin historian Blair Rudes helped dispel the widely-held belief that the name meant “great shellfish bay.”
  • There were many different Native American tribes in the region before Europeans arrived, but the dominant group were Algonquin speakers known collectively as the Powhatan tribes.
  • In 1524, Italian Captain Giovanni da Verrazano became the first recorded European to enter the Chesapeake Bay.
  • In 1608, Captain John Smith set off on the first of two voyages where he charted the land and waterways, and later drew an elaborate and remarkably accurate map of the Chesapeake Bay.

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