- A. E. Dick Howard papers, 1928/20171
- A. Willis Robertson Papers, 1921/1988, bulk 1946/19661
- Abner Johnson Leavenworth Papers, 1825/18611
- Abraham Davenport Ledger, 1804/18331
- Abraham Grove Account Book, 1815/18501
- Adam Empie Papers, 1811/2004, bulk 1811/18501
- Adam Rinica and George Rinica Account Book, 1822/18481
- Adams Papers, 1782/18901
- Administration records collection, 1776/19762
- Advisory Committee Research Collection, 1772/20175
- Alabama Collection, 1823/18931
- Albert R. Gallatin papers, 1795/18281
- Alderman family papers, 1779/19613
- Alexander Brown Papers (I), 1815/19102
- Alexander McNutt Glasgow Family Papers, 1823/19032