Mason Neck NWR was established in 1969 for the protection of nesting, feeding, and roosting habitat for the Bald eagles. It was the first federal refuge established specifically for the (then endangered) Bald eagle. The refuge is part of the Potomac River NWR Complex.

The refuge, situated along the Potomac River on the Mason Neck peninsula, consists of 2277 acres of oak-hickory forest, freshwater marshes, and has 4.4 miles of shoreline. The refuge has the largest fresh water marsh in Northern Virginia, the largest Great Blue heron rookery in the Mid-Atlantic region (over 1400 nests), is a designated RAMSAR site, and hosts over 200 species of birds, 31 species of mammals, and 44 species of reptiles and amphibians.

Eagles use the mature forests for shelter and nesting sites and the marshes, bays, and river for foraging and hunting. Seven Bald eagle nests occur on or adjacent to the refuge along with an eagle roost and a wintering population of 50-60 birds. The refuge was listed as one of the top ten sites in the country for viewing Bald eagles.

The recorded history of Mason Neck began in 1775 with the construction of nearby Gunston Hall, home of George Mason. Mason was an author of the Virginia Bill of Rights, predecessor to the United States Bill of Rights. Logging occurred repeatedly through the 1800's and 1900's and today remnants of the sawmills can still be found on the refuge. By the 1960's the timber had grown back but a new threat had arisen. Residential development threatened to destroy the integrity of the Mason Neck peninsula and endanger nesting eagles. The Nature Conservancy along with local citizens lead by "Eagle Lady" Liz Hartwell fought to stop the developers. They brought the beauty and significance of the eagle nesting sites and the expansive Great Marsh to the attention of local, State and Federal agencies. The refuge was created in 1969 as the first National Wildlife Refuge established for the protection of the then endangered bald eagle.