Chesapeake Bay

Chesapeake Bay is the largest estuary in the United States, lying in the Mid-Atlantic region between Maryland and Virginia with the Delmarva Peninsula to its east, formed roughly 10,000 years ago when rising sea levels flooded the valley of the Susquehanna River. It extends about 320 kilometers from north to south, narrowing to as little as 4.5 kilometers wide and widening to 48 kilometers, with an average depth of only about 6.4 meters and a maximum depth of 53 meters. Its drainage basin covers roughly 166,530 square kilometers across six states and Washington, D.C., and its shoreline, including islands and tributaries, totals nearly 18,800 kilometers, making it a defining feature of the Mid-Atlantic coast and an important shipping and recreational waterway.