The Federal Triangle, Washington DC


The Ariel Rios Federal Building (New Post Office)
Photo courtesy of GSA

The Federal Triangle is located between Pennsylvania Avenue, Constitution Avenue and 15th Street, NW and is part of the Pennsylvania Avenue National Historic Site. It is comprised of a unified group of important and prominent Federal office buildings. The 1926 Public Buildings Act, which permitted the Government to hire private architects for the design of Federal buildings, heralded the beginning of the country’s largest public buildings construction program. Among the most significant early projects generated under the new legislation was the development of a 70-acre site (now known as the Federal Triangle) between the Capitol and the White House. U.S. Secretary of the Treasury Andrew W. Mellon and a distinguished Board of Architectural Consultants, headed by Edward H. Bennett of the Chicago architectural firm of Bennett, Parsons, and Frost, developed design guidelines for the site.

Under Bennett’s direction, each member of the Board of Architectural Consultants designed one of the buildings in the Federal Triangle complex. The goal of the project was to provide each Government agency or bureau with a building that would address its functional needs, while combining the individual buildings into a harmonious, monumental overall design expressive of the dignity and authority of the Federal Government. Limestone facades, red-tile hipped roof, and classically inspired colonnades are common features of the Federal Triangle buildings.

Located at 12th Street and Pennsylvania Avenue, the Ariel Rios Federal Building, also known as the new Post Office, was designed by William Adams Delano and William T. Aldrich and constructed between 1931-1935. Inspired by the Place Vendome in Paris, the Ario Rios Federal Building was intended to be a central feature of the Federal Triangle. The central section of the tri-unit building is comprised of two huge, back to back, semi-circular units with side wings. The hemicycle formed by the building’s curve was to be mirrored by a similarly curved façade built across 12th Street on the site of the Old Post Office Building. However, preservation efforts in the 1970’s saved the Old Post Office from demolition and the second half of the grand plaza was never finished as designed. The Ariel Rios Federal Building’s seven-story spiral marble staircase is a prominent element of the interior. A chandelier hangs in the center of the staircase and has exposed bulbs to illuminate each floor. It terminates in a dramatic chrome and brass globe.

The Andrew W. Mellon Auditorium at 14th Street and Constitution Avenue was designed by Arthur Brown, Jr. and constructed between 1928–1934. Originally the Treasury Department Auditorium, the building was renamed for Andrew Mellon who oversaw the development of the Federal Triangle complex while serving as Secretary of the Treasury from 1921 to 1932.

The Andrew W. Mellon Auditorium
Photo courtesy of GSA

The Mellon Auditorium is the central component of a three-part complex and is flanked by the Interstate Commerce Commission and the U.S. Customs Service (originally the Department of Labor). Arched, open portals topped by 45 foot tall columns connect the individual buildings. The monumental, temple-form building has a pedimented portico supported by six Doric columns. The sculpture within the pediment is Edgar Walter’s Columbia.

The Auditorium was intended to remedy the Federal Government’s lack of assembly space for large gatherings and ceremonial occasions which existed prior to its construction. The magnificent assembly room seats 2,500 and is the Government’s largest auditorium for ceremonies, receptions, and other events. The rest of the building contains small meeting rooms, a series of offices, and lobbies. President Franklin D. Roosevelt initiated the Selective Service System lottery in the Auditorium on October 29, 1940. The North Atlantic Treaty was signed here on April 4, 1949, with President Harry Truman, Secretary of State Dean Acheson, and ministers of 11 other nations in attendance.

The Department of Commerce Building, officially known as the Herbert C. Hoover Building, is located at 14th Street and Constitution Avenue. Designed by Louis Ayres and constructed between 1927–1932, the Commerce Department building is named after President Hoover who served as Secretary of Commerce during the agency’s early development. It was the largest office building in the world at the time of its completion in 1932.

The Hoover Building contains more than 3,300 rooms joined by unbroken corridors 1,000 feet long. Flexible partitions, rather than permanent walls, were a part of the original design for many of the offices to allow for inevitable changes in Departmental organization. Six interior courtyards provide light and air to the inner offices. The rectangular building measures approximately 320 ft east-west by 1020 ft north-south, and forms almost the entire west side of the Triangle from Constitution Avenue to E Street. There is a Doric colonnade on three sides. The 15th Street façade stretches almost 3 city blocks and has four pedimented pavilions featuring sculptures by James E. Fraser. The National Aquarium is located in the basement and has been open to the public since the building was completed in 1932. On the first floor, facing Pennsylvania Avenue, is the White House Visitors Center. It is located in the former Patent Search Room.

The Department of Justice
Photo courtesy of Dept. of Justice

Located on a prominent trapezoidal lot bounded by Constitution and Pennsylvania Avenues and Ninth and Tenth Streets, the Department of Justice building was designed by the Philadelphia architectural firm Zantzinger, Borie and Medary and was constructed between 1931 and 1935. The Classical Revival style building is distinguished by Art Deco architectural elements and its innovative use of aluminum for details that were traditionally cast in bronze. All entrances to the building feature 20-foot-high aluminum doors that slide into recessed pockets. Interior stair railings, grilles, and door trims are aluminum, as are Art Deco torchères, doors for the building’s 25 elevators, and more than 10,000 light fixtures. The two-story Great Hall features Art Deco light fixtures and a terra-cotta tile floor with gray marble borders. The Law Library, located on the fifth floor, is a two-story room distinguished by a pair of tall Art Deco lights and a 20-panel mural by Maurice Sterne. Fifty-seven sculptural elements designed by C. Paul Jennewein adorn the building. Sixty-eight murals completed between 1935 and 1941 depict scenes of daily life from throughout American history and symbolic interpretations or allegorical themes relating to the role of justice in our society.

Old Post Office Tower is open to the public during the summer from 8:00 am to 10:45 pm daily; Winter 10:00 am to 5:45 daily. For more information call 202/606-8691.

The National Aquarium (in the Hoover Building) is open daily (except Dec. 25th) from 9:00 am to 5:00 pm. For more information call 202/482-2825.

White House Visitors Center (in the Hoover Building) is open daily from 7:30 am to 4:00 pm. For more information call 202/208-1631.

Ariel Rios, Mellon Auditorium, Interstate Commerce Commission and U.S. Customs Service are working offices of the Federal civilian workforce. Public events are scheduled periodically.

Metro stop: Federal Triangle