- American Locomotive Company/Baldwin Locomotive Works Illustrations, 1900/19251
- Ann A. Hertzler Collection, 1863/2013, bulk 1974/20002
- Ann Eve Moss Papers, 1920/19901
- Anna Burton Ellett Collection, 1751/19321
- Anne H. Price Yates Papers, 1904/1985, bulk 1975/19852
- Anne Price Yates Papers II, 1898/20053
- Annie M. Hale Sheet Music Collection, 1892/198713
- Antoine Gaujot and Julien E. Gaujot Papers, 1840/19994
- Archer Lawrie Sheet Music Collection, 1879/19355
- Architectural League of New York: Archive of Women in Architecture Records, 1892/19762
- Armed Services Edition Collection, 1913/19451
- Arthur B. Massey Papers, 1902/19614
- Arthur M. Squires Papers, 1888/1987, bulk 1940/198717
- Arthur W. Grove Family Papers, 1900/19572
- Association for the Preservation of Virginia Antiquities, Montgomery County Branch Papers, 1754/1996, bulk 1958/19835