Mallows Bay-Potomac River National Marine Sanctuary is home to a diverse collection of shipwrecks, as well as an array of wildlife inhabiting the surrounding area of Mallows Bay. Skeletons of over 100 wooden and steel-hulled steamships from the 1700s to the 1900s, called the Ghost Fleet, are protruding from the water line waiting to be explored. While enjoying the waters on a self-guided tour, wildlife such as osprey, largemouth bass, turtles, and beavers can be viewed both on the shore and on the water. From kayaking down this sanctuary or fishing in the river, visitors can learn about these waters that represent American heritage.

The sanctuary is located east of the Virginia border, from Mallows Bay Park in Maryland south to Widewater Park in Virginia.