- Historical and Governing Records, 1841-192539
- History of the Charleston Fire Department, 19531
- Holloway Family Collection1
- Home Movies from Moving Image Research Collections24
- Horace Gilbert Smithy, Jr., M.D. Papers152
- Horlbeck Brothers Records, 1824-18603
- Housworth Stereographs Collection41
- Hunley Artifact Collection – Personal Artifacts40
- Hunley Artifact Collection – Submarine Components and Tools18
- Hurricane Hugo Elevation Maps16
- Hutson Lee Papers, 1858-186515
- Illustrated Newspaper Clippings, 1840-191728
- Images from the Records of the Charleston County Public Library181
- Invoice of rice sales for Anthony Clarkson, 1762 Oct. 301
- Irish Heritage Oral History Collection13
- Irish Volunteers Company records, 1798-19292
- Isaac Harby Family Papers6
- Isaiah Bennett Papers, ca. 1932-200257
- Isaiah DeQuincey Newman Papers39
- J. F. R. Papers, 1849-18551