- A. Willis Robertson Papers, 1921/1988, bulk 1946/19661,119
- A.B. Stickney, Compiler, Genealogical Materials, 1838/19591
- A.E.S. Stephens Papers, 1949/196110
- A.J. Morrison Collection, 1754/19751
- Abbye A. Gorin Architectural Collection, 1940/2006, bulk 1995/20062
- Abraham Anson papers, 1939/200534
- Abraham Lincoln Collection, 1860/19651
- Academic Departments - Record Group 92
- Ackerly Family Papers14
- Ada Haldeman Ford, Suffragist, Papers, 1900/19701
- Adagio Press Collection, 1957/19933
- Adalbert J. Volck Collection of Etchings, 1861/19794
- Adam Empie Papers, 1811/2004, bulk 1811/18503
- Adams T. Rice papers, 1922/19604
- Addison H. Smith papers, 1917/1970, bulk 1917/19222