Nanjemoy is a large rural area in Charles County, Maryland, United States more or less bounded by the Nanjemoy Creek and the Potomac River. It shares its name with a Native American tribe. Nanjemoy houses the largest great blue heron rookery in the east north of Florida. A radio astronomical observatory is located near the Potomac River; it used to be operated by the U.S. Naval Research Laboratory but was later transferred to the Nanjemoy Creek Environmental Education Center. The county government maintains a large community center building in the village center which offers many services for a diverse population. There are also two children's camps and a sheriffs' training facility. Famous people born in Nanjemoy include Raphael Semmes, captain of the Confederate battleship "Alabama", and Matthew Henson, who with Robert Peary discovered the North Pole.