* Fort McHenry National Monument and Historic Shrine
Baltimore, Maryland (Presidential Proclamation No.2795, July 2, 1948)
* Flag House Square (Mary Pickersgill's "Star Spangled" House)
Baltimore Maryland (Public Law 83-319, approved March 26, 1954)
* United States Marine Corp Memorial (Iwo Jima)
Arlington, Virginia (Presidential Proclamation No.3418, June 12, 1961)
* On the Green of the Town of Lexington
Massachusetts (Public Law 89-335, approved November 8, 1965)
* The White House
Washington, DC. (Presidential Proclamation No.4000, September 4. 1970)
* Washington Monument
Washington, DC. (Presidential Proclamation No.4064, July 6,1971, effective July 4, 1971)
* United States Customs Ports of Entry
which are continually open (Presidential Proclamation No.4131, May 5, 1972)
* Grounds of the National Memorial Arch in Valley Forge State Park
Valley Forge, Pennsylvania (Public Law 94-53, approved July 4, 1975)
http://www.crwflags.com/fotw/Flags/us_24hr.html
[Added reference link - McG]