- 1x1 Japan Exhibition Materials, 1965-2024, 20242
- A. E. Dick Howard papers, 1928/201739
- A. H. Hand Papers, 1835/20091
- A. Jane Duncombe Architectural Papers, 1952/20022
- A. Patrick L. Prest, Jr. papers, 1941/201419
- A. Willis Robertson Papers, 1921/1988, bulk 1946/19661
- ALIVE (ALexandrians InVolved Ecumenically) Records (MS300), 1969/199511
- Abbye A. Gorin Architectural Collection, 1940/2006, bulk 1995/20061
- Abraham Anson papers, 1939/200516
- Academic Affairs: Academic Program Reviews, 1976/2018, bulk 1992/20181
- Adagio Press Collection, 1957/19933
- Adam Empie Papers, 1811/2004, bulk 1811/18501
- Administrative Management Society records, 1941/1987, bulk 1941/198730
- Admiral Thomas J. Lopez Papers, 1973/201412
- Advisory Committee Research Collection, 1772/201720