- Account book (N.H.), 1856/18742
- Accounts, 19th Century, 1836/18971
- Ackerly Family Papers6
- Adalbert J. Volck Collection of Etchings, 1861/19792
- Adam Empie Papers, 1811/2004, bulk 1811/18503
- Adams Papers, 1782/18902
- Adee Family Papers, 1862/18652
- Adelaide Colcock Papers, 1863/18702
- Adele Goodman Clark papers, 1849/19784
- Adin B. Underwood Papers,, 1861/19263
- Administration records collection, 1776/197615
- Admiral John Randolph Tucker Papers, 1865/189710
- Adolphus DeBussey, Soldier, Civil War Letters, 1861/1998, bulk 1861/18715
- Adolphus P. Howard Papers, 1850/19381
- Adolphus P. Howard Papers, 1854/19041