The William Jefferson Clinton federal building is composed of two distinct historic buildings. Completed in 1934, the northern half of the building was originally known as the New Post Office Building. Replacing the Old Post Office, located across 12th Street, the new building was intended to consolidate and house the quickly expanding Post Office Department. The vast curved facades and hour-glass shape of the building serve as a monument to the original design of the Federal Triangle, which included two large circular plazas to either side of the building. Today the building operates as the headquarters of the U.S. Environmental Protection Agency.
The southern portion of the Clinton building was designed by San Francisco architect Arthur Brown and spans Constitution Avenue between 12th street and 14th street. Originally designed to house the Interstate Commerce Commission, Department of Labor, and Departmental Auditorium, the building is a dramatic example of the Classical Revival architectural style.