- BLSA: Black Law Students Association records, 2014/20214
- Baba Freeman Reston, Virginia collection, 1966/20072
- Baba Freeman Reston, Virginia, collection, 1966/20071
- Barbara Cary Johnston Willard Scrapbook, 1800/20061
- Barbara H. Dunn Papers, 1970/20035
- Barbara Lustbader New York City playbills collection, 1957/201216
- Barbara McKnight Benham papers, 1966/20212
- Barnette Collection, Lawyer, Businessman, Educator, Philanthropist, and Chairman Emeritus of Bethlehem Steel Corporation, 1905/202010
- Barton Myers III Papers, 1988/20063
- Base Hospital No. 41 collection, 1905/20091
- Baseball records, 1908/20242
- Ben Benson Collection, 1789/20151
- Benjamin Huddle Diary, 1861/20062
- Benjamin L. Wigfall Artist Archives and Mary Carter Wigfall Personal Papers, 1880/202321
- Berkeley Garden Club records, 1970/19961