Two designations that are sometimes confused with one another are The National Historic Landmarks and The National Register of Historic Places

About 76,000 enties nationwide are in the National Register, and within that group are only 2300 that are National Historic Landmarks.

National Register places are of historic interest on a local or state level, while National Landmarks meet a tougher standard of being significant to the entire nation.   Both the National Historic Landmarks and the National Registry Programs are administered by the National Park Service under the Secretary of the Interior .   These programs began in 1966 when the U.S. Congress passed the National Historic Preservation Act .

Virginia has 117 National Historic Landmarks.

Loudoun County has the following 6 properties
listed as National Historic Landmarks.

Balls' Bluff Battlefield and National Cemetery (Leesburg)
Dodona Manor - The George C. Marshall House (Leesburg)
The General Billy Mitchell house (Boxwood) (Middleburg)
Oak Hill - residence of President James Monroe (Leesburg)
Oatlands Plantation (Leesburg)
Waterford Historic District (Waterford)

Clarke County has the following 2 properties
listed as a National Historic Landmarks.

Greenway Court - Estate of Thomas Lord Fairfax (White Post)
Saratoga - home of General Daniel Morgan (Boyce)

Fauquier County has no National Historic Landmarks.

Earlier in 1966 Virginia established its own Virginia Historic Landmarks Commission