- Inventory of S.C. Church Archives284
- Invoice of rice sales for Anthony Clarkson, 1762 Oct. 301
- Irish Heritage Oral History Collection32
- Irish Volunteers Company records, 1798-19292
- Is part of: William Lynch Postcard Collection1
- Isaac Harby Family Papers6
- Isaac Hayne Journal: Register, ca. 1764-17811
- Isaac Rosenberg: Early Poetry and Related Documents from the Joseph Cohen Collection of World War I Literature10
- Isaac Samuel Leevy Papers, 1905-197334
- Isabella Sarah Porcher Plantation Prescription Book1
- Isaiah Bennett Papers, ca. 1932-200283
- Isaiah DeQuincey Newman Papers1,466
- J. Arthur Brown Papers, 1937 - 1988380
- J. F. R. Papers, 1849-18551
- J. Marion Sims Letters4
- Jack Keilen Slide Collection593
- James Calvin Hemphill, Sr. Architectural Collection98
- James E. Campbell papers, 1930-2009107
- James Glen Papers102
- James H. Davis and John S. Davis U.S. Marine Corps Oral History Collection4