The first of the Triangle's buildings, the Romanesque-Revival Old Post Office, was constructed in 1891-1899. The Neo-Classical Beaux Arts District Building followed in 1904-1908.
Tthe bulk of the area's buildings and its overall design were developed between 1928 and 1938 under the direction of a consultant board of architects to Secretary of the Treasury Andrew Mellon, popularly known as the Mellon Board. Designed by the leading architects of the period, the Mellon Board's handsome Neo-Classical ensemble consists of nine enormous federal buildings constructed around a series of outdoor plazas and inner courts. It is this country's most imposing example of the monumental civic center concept, a planning ideal in the early decades of the twentieth century.
DC listing: March 7, 1968
National Register eligible
Within Pennsylvania Avenue NHS
The buildings found within Federal Triangle boundary are:
Old Post Office: Built 1891-99 (Willoughby J. Edbrooke, architect); see separate listing
District Building: Built 1904-08 (Cope and Stewardson, architects); see separate listing
Commerce Building: Built 1927-32 (York and Sawyer, architects)
Post Office Department: Built 1931-34 (Delano and Aldrich, architects)
Labor Department, Interstate Commerce Commission, and Departmental Auditorium: Built 1931-35 (Arthur Brown, architect)
Grand Plaza and Great Circle
Internal Revenue Service: Built 1927-35 (Louis Simon, architect)
Justice Department: Built 1931-35 (Zantzinger, Borie and Medary, architects)
National Archives: Built 1931-37 (John Russell Pope, architect); see separate listing
Federal Trade Commission: Built 1937-38 (Bennett, Parsons and Frost, architects)