A river sanctuary of ghost ships, ancient shorelines, and tidal Transition zone ecology in the Chesapeake watershed.
Mallows Bay, Potomac River National Marine Sanctuary
Mallows Bay–Potomac River National Marine Sanctuary is a federally protected marine sanctuary on a roughly 18-square-mile stretch of the tidal Potomac River in Charles County, Maryland, about 40 miles south of Washington, D.C. It was designated on September 3, 2019 as the fourteenth National Marine Sanctuary in the United States, the first in the Chesapeake Bay watershed, and the first such designation since 2000. The sanctuary is best known internationally for the Ghost Fleet, a group of 118 partially submerged wooden steamships in the northeastern corner of Mallows Bay that together form the largest shipwreck fleet in the Western Hemisphere.
Beyond the Ghost Fleet, the sanctuary is a layered historic landscape. It holds archaeological evidence of human presence along the Potomac reaching back roughly 12,000 years, sites associated with the Piscataway and Patawomeck peoples, places tied to African American life from the 17th century onward, Revolutionary War and Civil War era wrecks, and evidence of the steamboat era and a once-active Potomac fishing industry. These multiple histories overlay an ecologically rich Transition-zone section of the river where fresh water from upstream mixes with tides from the Chesapeake Bay.
The sanctuary's protected waters are also a working ecological system. Submerged aquatic vegetation beds, tidal marshes, and the vegetation-covered shipwrecks themselves support fish, invertebrates, birds, beavers, and reptiles, while a NOAA water-quality buoy and partner research programs track environmental change. Mallows Bay itself has been listed on the National Register of Historic Places since 2015, and the sanctuary is now a key component of the Southern Maryland National Heritage Area and a focal site for heritage tourism in the region.
