The Chesapeake Bay is big—200 miles from its head at Havre de Grace, MD, to Norfolk, VA, and 35 miles across at its widest point, near the mouth of the Potomac. But the watershed that drains into the Bay is much bigger still.
The Chesapeake Bay watershed covers 64,000 square miles encompassing parts of six states—Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia—and the entire District of Columbia. You could live more than 100 miles from the Chesapeake Bay and still be in part of its watershed.
Nearly 17 million people live in the Chesapeake watershed, and the population is growing by roughly 157,000 each year. That’s a lot of people, and all the water they use for drinking, recreation, industries, schools, and other business ends up in the Bay. The actions of all those people in the watershed have a significant influence on the health of the Bay.
More than 100,000 streams and rivers—called tributaries—eventually flow into the Chesapeake. Everyone who lives in the Bay watershed is within a few minutes of one of these streams and rivers. Each of these tributaries has its own watershed, and these smaller sub-watersheds make up the Chesapeake’s large and complex ecosystem. Protecting the entire watershed is key to the long-term health of Chesapeake Bay and everyone and everything that lives here.
The major rivers flowing into the Bay are characterized by the landscape they traverse. The Susquehanna River, running 444 miles through high country from its headwaters near Cooperstown, NY, to where it meets the Bay is the largest source of freshwater for the Chesapeake Bay system. The James and Potomac rivers to the west also rise far up into mountains and drain large areas. Other western rivers—Patuxent, Rappahannock, and York—produce large flows of freshwater, too, causing the western half of the Bay to be less salty, more silty, and generally more active.
The eastern rivers of the Bay, by contrast, cut across most of the low, flat countryside of the Delmarva Peninsula and flow through large expanses of marshy wetlands. The largest of these are the Pocomoke, Wicomico, Nanticoke, Choptank, and Chester. They do not drain upland areas or have much, if any, fall in height from headwater to mouth. They are tidal for most of their length and notably salty or brackish.
Learn More about the Chesapeake Bay Watershed