Bay Facts

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

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

In 1524, Italian Captain Giovanni da Verrazano became the first recorded European to enter the Chesapeake Bay.

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

The widest point of the Chesapeake Bay measures 35 miles, and is located near the mouth of the Potomac River.

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

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.

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

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

At 4,863 feet above sea level, Spruce Knob is the highest point in the Chesapeake watershed.

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

More than 1,800 vessels have met their end in Bay waters, lying broken and battered on the Bay's floor.

The narrowest point of the Chesapeake Bay measures 3.4 miles, and is located near Aberdeen, Maryland.

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.

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.

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