Bay Facts

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.

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.

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

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

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

The Chesapeake Bay is home to 26 different species of submersed aquatic vegetation (SAV), including freshwater plants, estuarine plants, redhead grass, and marine species.

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

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

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

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

There are twelve known species of shark that have been sighted in the Chesapeake Bay, with only five considered a common occurrence—smooth dogfish, sand tiger shark, sandbar shark, spiny dogfish, and bull shark.

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

Salinity is highest at the mouth of the Chesapeake Bay, where water from the Atlantic Ocean enters.

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

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.

At filter feeders, oysters can filter up to 50 gallons of water a day.

The 195-mile-long Rappahannock River is the longest free flowing river in the Chesapeake Bay 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).

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.