- Alfred Beckley (1802-1888) Papers, 1832/18561
- Alfred Leyburn Papers, 1823/1899, bulk 1830/18391
- Alfred Spates Papers
1843-19091
- Alice Rice Jaffe Papers, 1807/1950, bulk 1919/19501
- Allen Family Papers, 1766/193327
- Allen-Johnson Family Papers, 1838/19473
- Allen-Kean-Laurence family letters, 1837/19602
- Alpheus Garrison Civil War Records, 1804/18881
- Alumni Association Records, 1833/2014, bulk 1950/20056
- Alvan Fisher Personal Papers (SC-33), 1822/18521
- Amos Johnson Ledgers, 1808/1861, bulk 1808/18211
- Amos Koontz Papers I, 1809/1965, bulk 1936/19651
- Ancella Bickley, Historian, Research Papers regarding African-Americans, 1775/2018, bulk 1970/201113
- Anderson Family papers, 1755/195827
- Andrew Delmar Hopkins Papers, 1787/19431