Bay Facts

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, reaching as high as 84 degrees in summer.

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

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

The Bay’s width ranges from four miles near Aberdeen, Maryland, to 30 miles near cape Charles, Virginia.

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’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.

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

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

The Bay produces about 500 million pounds of seafood per year.

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 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.

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.

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.

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