Elizabeth Hartwell Mason Neck National Wildlife Refuge in Virginia occupies Mason Neck on the Potomac River at Belmont Bay and adjoins Mason Neck State Park as part of the Potomac River National Wildlife Refuge Complex. Established in 1969 and managed by the United States Fish and Wildlife Service, it was the first federal refuge created specifically to protect the bald eagle, giving it a significant place in American wildlife conservation. The refuge encompasses 2,277 acres, 4.4 miles of shoreline, extensive oak and hickory forest, and northern Virginia’s largest freshwater marsh. It was later renamed for local activist Elizabeth S. Hartwell, whose efforts helped save Mason Neck from development.