Watersheds
The Chesapeake Bay watershed encompasses parts of six states — Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia — and the entire District of Columbia.
A watershed is an area of land that drains to a particular river, lake, bay or other body of water. We all live in a watershed: some are large (like the Chesapeake), while others are small (like your local stream or creek). Watersheds are sometimes called "basins" or "drainage basins."
The Chesapeake Bay Watershed
The Chesapeake Bay watershed stretches across more than 64,000 square miles, encompassing parts of six states — Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia — and the entire District of Columbia.
The Chesapeake's land-to-water ratio (14:1) is the largest of any coastal water body in the world. This is why our actions on the land have such a significant influence on the health of the Bay.
Threading through the Chesapeake watershed are more than 100,000 streams and rivers — called tributaries — that eventually flow into the Bay. Everyone in the Chesapeake Bay watershed lives within a few minutes of one of these streams and rivers, which are like pipelines from our communities to the Bay. Each of these tributaries has its own watershed, which are sometimes referred to as "sub-watersheds" or "small watersheds" within the larger Chesapeake watershed.
Find Your Watershed
Enter your zip code into the EPA's Find Your Watershed widget to learn about the watershed(s) you live in.
- Why Watersheds?: Sideshows and other resources from the Center for Watershed Protection on the importance of watersheds.
- It's All in the Watershed: A collection of stories from the Smithsonian Environmental Research Center about the history and ecology of the Chesapeake Bay watershed.
- Watersheds: Frequently asked questions about watersheds from the U.S. Environmental Protection Agency.