Pennsylvania Avenue National Historic Site is a National Historic Site in the city of Washington, D.C. Established on September 30, 1965, the site is roughly bounded by Constitution Avenue, 15th Street NW, F Street NW, and 3rd Street NW. The historic district includes a number of culturally, aesthetically, and historically significant structures and places, including Pennsylvania Avenue NW from the White House to the United States Capitol, the Treasury Building, Freedom Plaza, Federal Triangle, Ford's Theatre, the Old Patent Office Building, the Old Pension Office Building, which now houses the National Building Museum, Judiciary Square, and the Peace Monument.
Pennsylvania Avenue N.W. in 2006: Freedom Plaza and its marble inlay of the L'Enfant Plan's 1791 street-grid diagram of Washington, D.C., visible on pavement (foreground), 1111 Pennsylvania Avenue (on left behind trees), Old Post Office Pavilion (on right), and the United States Capitol (background)
Image: Pennsylvania Avenue Historic Site boundaries
Pennsylvania Avenue and 7th Street in 1839 with the First Unitarian Church on the northeast corner of 6th Street and Pennsylvania Avenue visible in the background
An 1860 watercolor of Pennsylvania Avenue at 6th Street with the not yet finished United States Capitol in the distance and the National Hotel on the left
Federal Triangle
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Federal Triangle is a triangular area in Washington, D.C. formed by 15th Street NW, Constitution Avenue NW, Pennsylvania Avenue NW, and E Street NW. Federal Triangle is occupied by 10 large city and federal office buildings, all of which are part of the Pennsylvania Avenue National Historic Site. Seven of the buildings in Federal Triangle were built by the U.S. federal government in the early and mid-1930s as part of a coordinated construction plan that has been called "one of the greatest building projects ever undertaken" and all seven buildings are now designated as architecturally historic.
Aerial view of Federal Triangle (center), the National Mall (on left), and Downtown Washington, D.C. (on right) in September 2006
A diagram of Federal Triangle as of 2009, showing all 10 key buildings in the complex
A 1923 photograph of Federal Triangle, including Pennsylvania Avenue (on left), the District Building (in foreground), the Post Office building, and Center Market (in background)
Center Market in the 1920s