You might be confused by the following places where the US Flag is flown 24 hours a day, by presidential proclamation or law:
Fort McHenry National Monument and Historic Shrine, Baltimore, Maryland (Presidential Proclamation No.2795, July 2, 1948).
Flag House Square, Albemarle and Pratt Streets, 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). Fifty flags of the United States are displayed at the Washington Monument continuously.
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).