Historical Note: After the addition of the new House and Senate wings in the 1850s, even before the great dome was completed in 1863, photographs of the period show flags flying over each new wing and the central east and west fronts.
The custom of flying the flags 24 hours a day over the east and west fronts was begun during World War 1. This was done in response to requests received from all over the country urging that the flag of the United States be flown continuously over the public buildings in Washington, DC.
Presidential proclamations and laws since that time authorize the display of the flag 24 hours a day at the following places:
Fort MeHenry 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).