Eighteen of the 29 National Trust Historic Sites (2/3rds) are National Historic Landmarks, as follows:
Acoma Sky City
African Meeting House (Boston)
Belle Grove
Chesterwood
Cliveden
Decatur House
Drayton Hall
Farnsworth House
Frank Lloyd Wright Home & Studio
Lyndhurst
Montpelier
Oatlands
Philip Johnson’s Glass House
President Lincoln’s Cottage
Robie House
Shadows-on-the-Teche
Woodlawn
Woodrow Wilson House
And although it is NOT a National Trust Historic Site, the National Trust’s Headquarters Building in Washington, DC is also a National Historic Landmark (the Andrew Mellon Building).