- O. H. Wienges World War II Collection3
- One Man's Dream - William Plumer Jacobs and Clinton, South Carolina8
- Online Exhibits at South Carolina Political Collections1
- Papers of the Cox and Chesnut Families, 1792-1858212
- Paul Hamilton Papers22
- Pee Dee District Dental Society Records, 1933-19881
- Periodic Reports to the Clemson University Board of Trustees23
- Philip Simmons Collection2
- Phillips Family Papers2
- Phillis Wheatley Literary and Social Club Papers5
- Pierrine Smith Byrd Papers, 1919-1991102
- Pinckney Family Papers, 1703-18476
- Pinckney-Means Family Papers, 1701-19831
- Polychronicon Illuminated Manuscript1
- Porcher Family History1
- Porcher Family Papers, 1740-1967 (bulk 19th century)1
- President's Reports to the Board of Trustees8
- Primary Sources for K-12, Pilot Project3
- Pringle-Garden Family Papers, 1701-18824
- R.P. Hamer business letters, 18875