- Account Books, 1782/18951
- Account book (N.H.), 1856/18741
- Accounts, 19th Century, 1836/18971
- Adam Empie Papers, 1811/2004, bulk 1811/18501
- Adams Papers, 1782/18901
- Addie Rogers Bound Sheet Music Collection, 1827/18601
- Adele Goodman Clark papers, 1849/19781
- Administration records collection, 1776/19761
- Adolphus P. Howard Papers, 1850/19381
- Adolphus P. Howard Papers, 1854/19041
- Advisory Committee Research Collection, 1772/20171
- African and African American photograph collection, 1850/19451
- Aileen Shafer, Collector, Material regarding African-Americans, 1829/18841
- Alabama Collection, 1823/18931
- Albert Frederick Wilson papers, 1840/19341