Bay Facts

Water temperatures in the Bay fluctuate widely throughout the year, reaching as high as 84 degrees in summer.

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.

Nine in ten watershed residents never toss food wrappers, cups or cigarette butts on the ground. Almost eight in ten watershed residents pick up litter when they see it.

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 watershed includes nearly 50 thousand miles of rivers, streams and creeks.

There are as many as 200 invasive species present in the Chesapeake Bay watershed that are causing some serious issues in an already-stressed ecosystem. Some examples include blue catfish, snakehead, zebra mussel, purple loosestrife, and nutria.

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

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.

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

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

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.

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.

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

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

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

Two of the United States’ five major North Atlantic ports—Baltimore and Hampton Roads—are on the Bay.

The surface area of the Bay and its tidal tributaries is approximately 4,480 square miles.