- A.B. Stickney, Compiler, Genealogical Materials, 1838/19591
- A.C.L. Gatewood Papers, 1801/19191
- A.M. Scott Correspondence, 1874/18821
- Abner Osburn, Physician, Papers, 1846/19011
- Adolphus DeBussey, Soldier, Civil War Letters, 1861/1998, bulk 1861/18712
- Adolphus P. Howard Papers, 1850/19381
- Adolphus P. Howard Papers, 1854/19041
- African American Photographic Portraits, 1880/19531
- Aileen Shafer, Collector, Material regarding African-Americans, 1829/18841
- Alan Clarke Railroad Research Papers, 1861/201228
- Albert Blakeslee White (1856-1941) Papers, 1888/19291
- Albert M. Reese (1872-1965) Papers, 1873/19541
- Allen D. Frankenberry, Soldier, Civil War Diaries and Memoir, 1862/1905, bulk 1862/18651
- Allen Family Papers, 1766/193327
- Alpheus Garrison Civil War Records, 1804/18881