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 (56,000 m2) of floor space.

The exterior of the building is faced in granite from a variety of New England sources, as well as Indiana limestone.

Charles Raduazo acted as the chief headhunter in an effort to scout and employ electrical engineers and mathematicians from New England's elite colleges.

[3] The building is named for John W. McCormack, a long-serving Boston Congressman who was Speaker of the House from 1962 to 1971.