Bay Facts

The area of the watershed is about 64,000 square miles.

There have been 10 U.S. presidents from the Chesapeake Bay watershed, including George Washington, Thomas Jefferson, James Madison, James Monroe, William Henry Harrison, John Tyler, Zachary Taylor, Woodrow Wilson, James Buchanan and Joe Biden.

While one-third of watershed residents have volunteered their time or donated their money to a charitable organization, less than two in ten volunteers have done so for an environmental organization.

There are 6,282,718 acres of accessible green space within the Chesapeake Bay watershed.

The 110-mile-long Patuxent River is the longest river to flow exclusively within the borders of Maryland.

A few deep troughs run along much of the Bay’s length and are believed to be remnants of the ancient Susquehanna River.

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.

Collectively, the Chesapeake’s three largest rivers—the Susquehanna, Potomac and James Rivers—provide more than 80% of the fresh water to the Bay.

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.

The deepest part of the Bay, located southeast of Annapolis near Bloody Point, is called “The Hole” and is 174 feet deep.

The Chesapeake Bay watershed has 150 major rivers and streams, but contains more than 100,000 smaller tributaries.

The Chesapeake Bay watershed contains three distinct geologic regions: the Atlantic coastal plain, the Piedmont plateau and the Appalachian province.

The Chesapeake Bay holds more than 18 trillion gallons of water.

Most of the water in the Bay, including in the middle portion of the Bay and its tidal rivers, is brackish–a mixture of salty and fresh, with a salinity level of greater than 0.5 ppt but less than 25 ppt.

The Susquehanna River is the Bay’s largest tributary, and contributes about half of the Bay’s freshwater (about 19 million gallons per minute).

There are nearly 1,800 local governments in the Bay watershed, including towns, cities, counties and townships.

There were many different tribes in the region before Europeans arrived, but the dominant group were Algonquian speakers known collectively as the Powhatan tribes.

Water temperatures in the Bay fluctuate widely throughout the year, dropping as low as 34 degrees in winter.

Mallows Bay is the final resting place for more than 200 historic shipwrecks dating back to the Revolutionary War. Commonly referred to as the “Ghost Fleet” of Mallows Bay, it is the largest collection of shipwrecks in the Western Hemisphere.