- Albert R. Gallatin papers, 1795/18281
- Alderman family papers, 1779/19612
- Alex Welch Survey Papers, 1786/18011
- Alexander Balmaine Memorandum Book, 1775/18202
- Alexander Brown Papers (II), 1748/19001
- Alexander Haight family collection, 1764/19763
- Alexander Haight family collection, 1764/19773
- Alexander, Fultz, and Willson Families Collection, 1770/19701
- Alexandria History Collection (MS240), 1767/200812
- Alexandria Library Company Records (MS002), 1794/20077
- Alexandria, Virginia City Records (MS019), 1750/1983, bulk 1825/18751
- Allen Family Papers, 1766/19337
- Ancella Bickley, Historian, Research Papers regarding African-Americans, 1775/2018, bulk 1970/20118
- Anderson Family papers, 1755/19587
- Andrew Delmar Hopkins Papers, 1787/19431