Bay Facts

The Chesapeake Bay was formed about 10,000 years ago when glaciers melted and flooded the Susquehanna River valley.

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 Bay itself is about 200 miles long, stretching from Havre de Grace, Maryland, to Virginia Beach, Virginia.

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).

Legislation proposed by Maryland’s Senator Chris Van Hollen and Representative John Sarbanes to incorporate the bay into the nation’s park system.

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

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

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

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

The Bay and its tidal tributaries have 11,684 miles of shoreline—more than the entire U.S. west coast.

The Chesapeake Bay Program was organized in 1983 to help lead and direct restoration in the Chesapeake Bay.

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.

Captain John Smith and his men sailed the Chesapeake Bay in a modest wooden boat called a shallop–an open wooden workboat such as a barge, dory, or rowboat that was small enough to row but also had one or two sails.

Half of pet owners always pick up after their pet, but one-third of pet owners seldom or never do so. Pet waste contains bacteria that can harm human health and contaminate the water we use for drinking, swimming and fishing.

The word Chesepiooc is an Algonquian word referring to a village "at a big river." In 2005, Algonquian historian Blair Rudes helped dispel the widely-held belief that the name meant “great shellfish bay.”