- Alexandria, Virginia City Records (MS019), 1750/1983, bulk 1825/18751
- Alfred Beckley (1802-1888) Papers, 1832/18561
- Alfred Leyburn Papers, 1823/1899, bulk 1830/18391
- Alfred Parkins Ledgers, 1845/18541
- Alfred Spates Papers
1843-19092
- Alice Rice Jaffe Papers, 1807/1950, bulk 1919/19501
- Allen Family Papers, 1766/193330
- Allen-Johnson Family Papers, 1838/19473
- Allen-Kean-Laurence family letters, 1837/19602
- Alpheus Garrison Civil War Records, 1804/18881
- Alphonso Smith Lectures on General Chemistry notebook, 18492
- Alston Gordon Dayton Papers, 1846/19392
- Alumni Association Records, 1833/2014, bulk 1950/20055
- Alvan Fisher Personal Papers (SC-33), 1822/18521
- American Missionary Society Papers, 1848/18821