Bay Facts
The Bay is full of interesting facts and trivia related to its history, wildlife, geography and more.
The Bay's largest tributary
The Susquehanna River is the Bay’s largest tributary, and contributes about half of the Bay’s freshwater (about 19 million gallons per minute).
3,600 species of plants and animals
The Bay supports more than 3,600 species of plants and animals, including 348 species of finfish, 173 species of shellfish, over 2,700 plant species and more than 16 species of underwater grasses.
Learn more80,000 acres of underwater grasses
Nearly 80,000 acres of underwater grasses grow in the shallows of the Chesapeake Bay and its tributaries. Young and molting blue crabs rely on underwater grass beds for protection from predators.
Learn more9.6 million acres of land
Approximately 9.6 million acres of land in the Bay watershed have been permanently protected from development by Bay Program partners.
Learn more4,863 feet above sea level
At 4,863 feet above sea level, Spruce Knob is the highest point in the Chesapeake watershed.
One million waterfowl
Nearly one million waterfowl winter on the Bay–approximately one-third of the Atlantic coast’s migratory population. The birds stop to feed and rest on the Bay during their annual migration along the Atlantic Migratory Bird Flyway.
Learn more84 degrees Fahrenheit
Water temperatures in the Bay fluctuate widely throughout the year, reaching as high as 84 degrees in summer.
85% of airborne nitrogen
Healthy forests can capture more than 85% of the nitrogen that falls onto them from the air.
12 species of shark
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.
500,000 Canada geese
More than 500,000 Canada geese winter in and near the Bay.
Learn moreThe Chesapeake Bay's first inhabitants
The first inhabitants of the Chesapeake Bay region are referred to as Paleo-Indians. They came more than 10,000 years ago from other parts of North America, drawn in by the abundance of wildlife and waterways.
Learn more21 feet deep
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.
Filtering drinking water
Forests and trees help filter and protect the drinking water of 75% of watershed residents.
Learn moreVolunteering with environmental organizations
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.
200 invasive species
There are as many as 200 invasive species present in the Chesapeake Bay watershed that are causing some serious issues in an already-stressed ecosystem. Some examples include blue catfish, snakehead, zebra mussel, purple loosestrife, and nutria.
Largest estuary in the United States
The Chesapeake Bay is an estuary: a body of water where fresh and salt water mix. It is the largest of more than 100 estuaries in the United States and third largest in the world.
Learn moreWhat is a shallop?
Captain John Smith and his men sailed the Chesapeake Bay in a modest wooden boat called a shallop–an open wooden workboat such as a barge, dory, or rowboat that was small enough to row but also had one or two sails.
60% of Chesapeake forests
Sixty percent of Chesapeake forests have been divided into disconnected fragments by roads, homes and other gaps that are too wide or dangerous for wildlife to cross.
Learn moreRemnants of an ancient river
A few deep troughs run along much of the Bay’s length and are believed to be remnants of the ancient Susquehanna River.
64,000 square miles
The area of the watershed is about 64,000 square miles.
Nearly 50 thousand miles of rivers, streams and creeks in one watershed
The Susquehanna River watershed includes nearly 50 thousand miles of rivers, streams and creeks.
What is brackish water?
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.
35 miles wide
The widest point of the Chesapeake Bay measures 35 miles, and is located near the mouth of the Potomac River.
Chesapeake National Recreation Area
Legislation proposed by Maryland’s Senator Chris Van Hollen and Representative John Sarbanes to incorporate the bay into the nation’s park system.