How a Building Changed the House: Cannon House Office Building

Historical Highlight

Historical Highlight

The Cannon House Office Building, completed in 1908, is the oldest congressional office building. The creation of offices for Members of Congress forever changed how the House of Representatives worked.

How could an office building change congressional work so much? With expanded space, committees could hold more public hearings, Members could meet with more constituents, and staff could accommodate the many requests that flowed into the House from citizens around the country.

In the half century before the Cannon building opened, the Capitol had become overcrowded to the point of bursting. New states entered the Union during the nation’s westward expansion, and membership in the House grew from 193 in 1865 to 391 when the building opened. Most Representatives had no office or staff, only a desk and chair in the noisy House Chamber. Committees had to fight for space just to hold a meeting. Vendors hawked sandwiches and souvenirs all over the building. The new office building, joined by a twin Senate office building in 1909, alleviated the pressure for space, gave each Member his own office, and allowed the Congress to address the challenges of the new century.

Northwest Corner, Cannon House Office Building, 1908/tiles/non-collection/c/cannon-nw-corner-web.xml
Image courtesy of the Architect of the Capitol Northwest Corner, Cannon House Office Building, 1908
President Theodore Roosevelt at the cornerstone laying ceremony, 1906/tiles/non-collection/c/cannon-roosevelt-cornerstone-web.xml
Image courtesy of the Architect of the Capitol President Theodore Roosevelt at the cornerstone laying ceremony, 1906
Cannon House Office Building Postcard, Collection of the U.S. House of Representatives
About this object
Joseph Cannon memorial plaque/tiles/non-collection/H/HOB_CA~1.xml
Image courtesy of the Architect of the Capitol Joseph Cannon memorial plaque
The Cannon building was planned to enrich the Capitol not only in space but also in appearance. The prominent firm of Carrère and Hastings designed it in the symmetrical, sculptural, and stately Beaux-Arts style, one that complemented but did not compete with the Capitol. The building is clad in marble and limestone and boasts 34 columns facing the Capitol, echoed by pilasters on the sides of the building. Originally there were 397 offices and 14 committee rooms, and the building was connected to the Capitol by an underground tunnel.

In the century since it opened, the Cannon building has been joined by the Longworth and Rayburn buildings on the House side of the Capitol and the Russell, Dirksen, and Hart buildings on the Senate side. While it retains its original character, the Cannon building today has gone through changes. In 1913, a fifth floor was added, and over time the offices were reconfigured from single rooms to multiroom suites. In 1962, the building was named for former Speaker of the House  Joseph Gurney Cannon.