The Kluczynski Federal Building is a modernist skyscraper in the downtown Chicago Loop located at 230 South Dearborn Street. The 45-story structure was designed by Ludwig Mies van der Rohe and completed in 1974 as the last portion of the new Federal Center. It is 562 feet (171 m) tall and stands on the site previously occupied by the Chicago Federal Building by the architect Henry Ives Cobb. It was named in honor of U.S. Congressman John C. Kluczynski, who represented Illinois's 5th congressional district from 1951 to 1975 after his death that year.