- A. Rufus Tonelson Papers, 1922/19751
- Adele Blow Chatfield-Taylor family papers, 1899/19772
- Adele Goodman Clark papers, 1849/19785
- Adolphus DeBussey, Soldier, Civil War Letters, 1861/1998, bulk 1861/18711
- Alan Clarke Railroad Research Papers, 1861/20123
- Albert Blakeslee White (1856-1941) Papers, 1888/19291
- Albert L. Sturm Papers, 1904/19881
- Alexander Farish Robertson Papers, 1867/19312
- Alexander Haight family collection, 1764/19761
- Alexander Haight family collection, 1764/19773
- Alexandria History Collection (MS240), 1767/200819
- Alexandria Library Company Records (MS002), 1794/20073
- Alfred C. Payne Collection, 1917/20031
- Algernon B. Chandler, Jr. Records, 1912/19283
- Alice Rice Jaffe Papers, 1807/1950, bulk 1919/19501