Bay Facts

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

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 formation of the Chesapeake Bay happened 35.5 million years ago when a meteor collided with Earth, forming a massive crater.

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

The mouth of the Chesapeake Bay is about 12 miles wide between its northern point near Cape Charles, Virginia, and its southern point close to Cape Henry, Virginia.

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

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

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

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.

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

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

During the winter, the Bay supports 87 species of waterbirds. Of these wintering waterbirds, 14 species rely on the Bay to serve as habitat for more than 10% of their continental populations.

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.

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

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

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

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.