Bay Facts

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

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

Eighty-six percent of watershed residents believe if people work together, water pollution can be fixed.

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

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

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.

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

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

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.

Forty-six percent of watershed residents never use toxic pesticides in or around their homes. You can evaluate a pesticide’s toxicity to judge the risk in using it, or make your own non-toxic pesticide with garlic, vinegar, cooking oil and other common household items.

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

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

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

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

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

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

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