- Adam Finch Collection, 1891/19331
- Adam T. Finch Papers, 1895/19261
- Addison Family Papers, 1890/18991
- Adin B. Underwood Papers, 1861/19261
- Administration records collection, 1776/197617
- Admiral John Randolph Tucker Papers, 1865/18971
- Advisory Committee Research Collection, 1772/201712
- African American Family Photographs, 1880/19601
- African American man tintype portrait, 1865/19001
- Alan R. Shirkey photograph collection, 1877/19172
- Albert C. Swindler Papers, 1862/1929, bulk 1862/18641
- Albert Frederick Wilson papers, 1840/19341
- Albert R. Gallatin papers, 1795/18281
- Alderman family papers, 1779/19616
- Alexander Brown Papers (I), 1815/19105