Wikimedia Commons has media related to National Historic Landmarks of the United States.

National Historic Landmarks (NHL) are buildings, districts, objects, sites, and structures, that are within the United States, or its territories and associated states, or foreign states; and designated by the United States Secretary of the Interior because they meet one or more of the following:

• sites where events of national historical significance occurred;
• places where prominent Americans lived or worked;
• icons of ideals that shaped the nation;
• outstanding examples of design or construction;
• places characterizing a way of life; or
• archaeological sites able to yield information.

All NHLs are also listed on the National Register of Historic Places (NRHP), but most NRHP properties are not designated NHLs.