Since then the Library of Congress has become the largest library in the world housing nearly 119 million items. The Library of Congress offers tours both in English and Spanish. Tours are guided and given in groups of 50. 4 p.m. Tours begin at the Thomas Jefferson Building visitor entrance. This private, non-profit organization accepts no government funds and maintains Mount Vernon through visitors fees and private donations.
Audio tours are available for an additional fee.
A guide to the Mount Vernon grounds is available online . Mount Vernon is open to the public from 9 a.m. until 5 p.m. March through October, and from 9 a.m. until 4 p.m. from November through February. The Smithsonian consists of 16 museums, the National Zoo, and a variety of research facilities. All musuems and the National Zoo are free and open to the public. Hours may vary for different exhibits and museums.