- Abolitionist Movement Collection, 1834/18881
- Abraham Lincoln Collection, 1860/19651
- Abraham Rudisill diary, 1875/18861
- Account Books, 1782/18951
- Accounts, 19th Century, 1836/18971
- Acker Family Diaries, 1880/19061
- Adalbert J. Volck Collection of Etchings, 1861/19791
- Adam Empie Papers, 1811/2004, bulk 1811/18501
- Adams Papers, 1782/18901
- Adele Goodman Clark papers, 1849/19781
- Adin B. Underwood Papers, 1861/19261
- Administration records collection, 1776/19761
- Admiral John Randolph Tucker Papers, 1865/18971
- Adolphus DeBussey, Soldier, Civil War Letters, 1861/1998, bulk 1861/18711
- Adolphus P. Howard Papers, 1850/19381