The Library of Congress is the nation’s oldest federal cultural institution and serves as the research arm of Congress. It is also the largest library in the world, with millions of books, recordings, photographs, maps and manuscripts in its collections.

The Library’s mission is to support the Congress in fulfilling its constitutional duties and to further the progress of knowledge and creativity for the benefit of the American people.

The Library of Congress occupies three buildings on Capitol Hill. The Thomas Jefferson Building (1897) is the original separate Library of Congress building. (The Library began in 1800 inside the U.S. Capitol.) The John Adams Building was built in 1938 and the James Madison Memorial Building was completed in 1981.

An agency of the legislative branch of the U.S. government, the Library includes several internal divisions (or service units), including the Office of the Librarian, Congressional Research Service, U.S. Copyright Office, Law Library of Congress, Library Services, the Office of Strategic Initiatives and the Office of Support Operations

Library’s organizational chart.