Cannon House Office Building

The Cannon House Office Building, often called the "Old House Office Building," completed in 1908, is the oldest congressional office building as well as a significant example of the Beaux-Arts style of architecture. It occupies a site south of the United States Capitol bounded by Independence Avenue, First Street, New Jersey Avenue, and C Street S.E. In 1962 the building was named for former Speaker of the United States House of Representatives Joseph Gurney Cannon.

Source: Wikipedia