<Tr> <Th> NRHP reference #</Th> <Td> 73002105 </Td> </Tr> <Tr> <Th> Added to NRHP </Th> <Td> April 11, 1973 </Td> </Tr> <P> The Old Post Office, listed on the National Register of Historic Places as the Old Post Office and Clock Tower and located at 1100 Pennsylvania Avenue NW in Washington, D.C., was begun in 1892, completed in 1899, and is a contributing property to the Pennsylvania Avenue National Historic Site . It was used as the city's main General Post Office until 1914 at the beginning of World War I, succeeding an earlier 1839 edifice, G.P.O. of Classical Revival style, expanded in 1866 on F Street, which later was turned over to the Tariff Commission and several other agencies (today, the Hotel Monaco). The Pennsylvania Avenue 1899 landmark structure functioned primarily as an federal office building afterward, and was nearly torn down during the construction of the surrounding Federal Triangle complex in the 1920s . It was again threatened and nearly demolished in the 1970s to make way for proposals for the completion of the enveloping Federal Triangle complex of similar Beaux Arts styled architecture government offices, first begun in the 1920s and 30s . </P> <P> Major renovations occurred in 1976 and 1983 . The 1983 renovation opened a whole new chapter in the structure's history and use, added a food court and retail space that together with the building's central atrium with an added roof skylight acquired the name of "Old Post Office Pavilion". A glass - walled addition on a former adjacent parking lot was added to the structure in 1991 . </P>

When was the old post office in washington dc built