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Chesapeake Bay
The largest estuary in the United States
Chesapeake Bay is the largest estuary in the United States, a long, drowned river valley reaching about 200 miles north from the Atlantic at the mouth of the Susquehanna. Flanked by Maryland and Virginia, it was formed when rising seas flooded the lower Susquehanna valley after the last Ice Age, and its enormous watershed drains parts of six states and Washington, D.C. before reaching the bay.
Famous for its blue crabs, oysters, and rockfish, the Chesapeake has been a center of American life since Jamestown, the first permanent English colony, was founded on one of its tributaries in 1607. Shallow, productive, and ringed by marshes and tidal rivers, it is also one of the most studied and intensively restored ecosystems in the country, the focus of a decades-long, multi-state cleanup effort to reverse pollution and dead zones.