The Office of the Architect of the Capitol (AOC) is responsible to the United States Congress for the maintenance, operation, development, and preservation of 16.5 million square feet of buildings and more than 450 acres of land throughout the Capitol complex.  This includes the House and Senate office buildings, the Capitol, Capitol Visitor Center, the Library of Congress buildings, the Supreme Court building, the U.S. Botanic Garden, the Capitol Power Plant, and other facilities.  The AOC also provides professional expertise with regard to the preservation of architectural and artistic elements entrusted to its care, and provides recommendations concerning design, construction, and maintenance of the facilities and grounds. 

Permanent authority for the care and maintenance of the United States Capitol was established by the Act of August 15, 1876 (19 Stat. 147; 40 U.S.C. 162–163). Architect’s are also responsible for the upkeep and improvement of the Capitol grounds, and the arrangement of inaugural ceremonies and other ceremonies held in the building or on the grounds. Legislation has been enacted over the years to place additional buildings and grounds under the jurisdiction of the Architect of the Capitol.

The Architect performs his duties in connection with the Senate side of the Capitol, the Senate Office Buildings, and the operation of the Senate Restaurants subject to the approval of the Senate Committee on Rules and Administration. In matters of general policy in connection with the House Office Buildings, his activities are subject to the approval and direction of the House Office Building Commission. The Architect is under the direction of the Speaker in matters concerning the House side of the Capitol; with respect to many administrative matters affecting operations on the House side of the Capitol complex he is subject to the oversight of the Committee on House Administration. He is responsible for the care and repair of works of art in the Capitol under the direction of the Joint Committee on the Library; in addition, he is responsible for the maintenance and restoration of murals and other architectural elements throughout the Capitol complex. The Architect of the Capitol also serves as the Acting Director of the United States Botanic Garden under the Joint Committee on the Library.

Dr. William Thornton, whose design for the Capitol was selected by President George Washington after a national architectural competition in 1793, is honored as the first Architect of the Capitol. Dr. Thornton’s assignment was limited to designing and supervising the construction of the new Capitol, under the direction of the Commissioners of the Federal District and the President of the United States. However, the role and responsibilities of the Architect have changed and grown as additional activities have been assigned to the office by Congress. Today, in light of the widespread activities under the jurisdiction of the Architect of the Capitol, the administrative function of the office is as important as the architectural and engineering responsibilities.