Collection
- Captain John Moore Collection, 1828 - 18395
- Carr Family Papers 1878-18847
- Catoctin Dam Project Papers 1974-19754
- Catoctin Farmers' Club Records 1868-198370
- Catoctin Mountain Alliance 1985-199545
- Caylor-Howser Postcard Collection 1898-1975293
- Charles Blair Tavenner Collection 1709-1980130
- Charles Bos Photograph Collection 1974-1987121
- Charles Smith/Robert Coe and James Monroe Bond and Court Notice 18222
- Charles, 3rd Earl of Tankerville, Will 1762 (1814 copy)2
- Chichester Collection ca. 1809, 18404
- Christian Nisewarner Diary 1 Aug 1860 - 31 Dec 18773
- Christopher Greenup Muster Rolls 17783
- Civil Defense Air Raid Instructions ca. 19502
- Civil War Letter, Leesburg, VA 23 June, n.y.2