- A. J. Davis Family Collection, 1874/2007, bulk 1874/19079
- Adam Finch Collection, 1891/19332
- Adam T. Finch Papers, 1895/19262
- Adin B. Underwood Papers,, 1861/19262
- Alexander Farish Robertson Papers, 1867/193116
- Alexander McNutt Glasgow Family Papers, 1823/19037
- Alleghany Chapter, National Society of the Daughters of the American Revolution Records,, 1890/20224
- Ann A. Hertzler Collection, 1863/2013, bulk 1974/20002
- Anna Burton Ellett Collection, 1751/19321
- Annie M. Hale Sheet Music Collection, 1892/19871
- Antoine Gaujot and Julien E. Gaujot Papers, 1840/19992
- Archer Lawrie Sheet Music Collection, 1879/19353
- Architectural League of New York: Archive of Women in Architecture Records, 1892/19762
- Arthur M. Squires Papers, 1888/1987, bulk 1940/19879
- Association for the Preservation of Virginia Antiquities, Montgomery County Branch Papers, 1754/1996, bulk 1958/19831