Chesapeake Bay Watershed Geography and Facts

The largest and at one-time most productive estuary in the United States, the Chesapeake Bay is an integral part of our natural and national history. Home to more than 17 million people and 3,600 species of plants and animals, the Chesapeake Bay watershed is truly an extraordinary place. Stretching across six states and the District of Columbia, the Bay watershed never ceases to amaze with its rich history, vital economic importance, and astounding beauty. Below are just a sampling of some of the impressive facts and numbers about our wondrous watershed. (read more)

Chesapeake Bay Watershed Map. Royalty Free.

The Chesapeake Bay

  • was formed nearly 12,000 years ago when glaciers melted and flooded the Susquehanna River valley;
  • is—most historians believe—named after the Algonquin word chesepiooc, meaning "great shellfish bay;"
  • is approximately  200 miles long, stretching from Havre de Grace, Maryland, to Norfolk, Virginia;
  • has an average depth of 21 feet (the deepest part of the Bay, a.k.a. "The Hole," is 174 feet deep and located off of Bloody Point, southeast of Annapolis, Maryland;
  • ranges from 3.4 to 35 miles wide;
  • holds more than 15 trillion gallons of water;
  • supports 348 species of finfish and 173 species of shellfish;
  • supports more than 3,600 species of plant and animal life, including 2,700 types of plants and more than 16 species of underwater grasses;
  • is fed by 50 major tributaries (or streams and rivers) every day—the largest of these are the Susquehanna, Potomac, Rappahannock, York, and James;
  • produces more than 500 millions pounds of seafood harvest each year.

The Chesapeake Bay Watershed

The Bay and the rivers and streams that feed it make up an impressive watershed, which:

  • is the largest estuary in United States and the third largest in the world;
  • supports more than 17 million people who live, work, and play within the watershed (10 million of these live along or near the Bay's shores);
  • has 64,000 square miles;
  • includes parts of six states (Virginia, Maryland, Delaware, West Virginia, Pennsylvania, New York) and Washington, D.C.;
  • has 11,684 miles of shoreline, including tidal wetlands and islands (that's more shoreline than the entire West Coast of the United States);
  • contains more than 100,000 rivers and streams;
  • has a 14:1 land-to-water ratio;
  • helps filter and protect the drinking water of 75 percent of Bay watershed residents through its forests and trees.
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