- Mills Family of Greenville263
- Mills Mill417
- Minutes of the Annual Conferences of the Baptist, Episcopal, Lutheran, Methodist, and Presbyterian Churches in South Carolina, 1785-1920396
- Miriam DeCosta Seabrook and Herbert U. Seabrook Papers, 1882-199569
- Miscellaneous South Carolina Pamphlets3
- Miscellaneous Textiles3
- Mitchell King Atlas, 1662-169531
- Modjeska Simkins Papers, 1909-1992167
- Modjeska Simkins: In Her Own Words33
- Monaghan Mill260
- Moonshine15
- Morris College Digital Collections40
- Moses Family Papers46
- Moth Specimens of Congaree National Park1,297
- Mrs. William Timmons Receipt Book, 183138
- Mulberry Castle: Land of My Dreams1
- Mulberry Plantation Journals, 1853-1908 (bulk 1853-1889)295
- Muriel and Marcus Zbar Collection21
- Muster Roll and Orders to the Commissary, 1772-17818
- Nathaniel Russell House Museum Collection20