- Alexander Brown Papers (I), 1815/19101
- Alexander Brown Papers (II), 1748/19001
- Alexander Haight family collection, 1764/19761
- Alexander Haight family collection, 1764/19771
- Alexander, Fultz, and Willson Families Collection, 1770/19701
- Alexandria History Collection (MS240), 1767/20081
- Alexandria Library Company Records (MS002), 1794/20071
- Alexandria, Virginia City Records (MS019), 1750/1983, bulk 1825/18751
- Alice Rice Jaffe Papers, 1807/1950, bulk 1919/19501
- Allen Family Papers, 1766/19331
- Alpheus Garrison Civil War Records, 1804/18881
- Ambler Papers, 1806/18361
- 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 1970/20111