The Chesapeake Bay is the sum total of its many tributaries. From its source in the Susquehanna to its mouth in the Atlantic ocean, many streams and rivers mingle and mix to form the largest estuary in the United States. The Potomac River, rising in the Appalachian mountains, is a major contributor to the Bay. To preserve it for future generations, keep its water pristine! “Potomac Sundown” by Lee Goodwin.