The John W. McCormack Post Office and Courthouse, formerly the United States Post Office, Courthouse, and Federal Building is a historic building at 5 Post Office Square in Boston, Massachusetts. The twenty-two story, 331-foot (101 m) skyscraper was built between 1931 and 1933 to house federal courts, offices, and post office facilities. The Art Deco and Moderne structure was designed in a collaboration between the Supervising Architect of the United States Treasury Department and the Boston architectural firm of Cram and Ferguson. It occupies a city block bounded by Congress, Devonshire, Water, and Milk Streets, and has over 600,000 square feet of floor space. The exterior of the building is faced in granite from a variety of New England sources, as well as Indiana limestone.