Federal Triangle

The 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. The Federal Triangle Washington Metro station serves Federal Triangle and the surrounding area.

The name "Federal Triangle" appears to have been a journalistic invention. The press made reference to a "Pennsylvania Avenue Triangle" as early as November 18, 1926, and use of this name continued as late as June 1929, but it was more common for the news media to refer to the area as "the Triangle" by 1927. This name was in use by 1928, even by government officials, and still used as of late 1934.

The Associated Press first used the term "Federal Triangle" (with both words capitalized) in 1935. The New York Times first used the term in 1936, although the paper's capitalization of both words did not become standardized until 1939. Definitions of the area also varied at first. Early news reports believed the eastern apex of Federal Triangle extended as far east and south as the Ulysses S. Grant Memorial in front of the United States Capitol. But almost all reports referred to Pennsylvania Avenue NW and 15th Street NW as the Triangle's northern and western boundaries.

The Senate Park Commission (also known as the "McMillan Commission") was formed by the United States Congress in 1900 to reconcile competing visions for the development of Washington, D.C. and especially the National Mall and nearby areas. The Commission's plan for development, the McMillan Plan, proposed the razing of all residences and other buildings on Lafayette Square and building tall, Neoclassical government office buildings with facades of white marble around the park to house executive branch offices. While the demolition of some nearby buildings occurred (notably the Hay-Adams Houses, Corcoran House, and a portion of the Decatur House grounds), the rapid expansion in the size and number of executive branch agencies in the 1910s, 1920s, and 1930s made the McMillan Plan's development of Lafayette Square impractical.

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