- Caloric1
- Calumet Baking Powder Co, General Foods.1
- Calumet Baking Powder Co., Chicago, Illinois4
- Camden Archives and Museum225
- Campbell's1
- Canned Salmon Industry1
- Carnation Company1
- Carnation Milk3
- Catholic Diocese of Charleston Archives3
- Certo2
- Charles B. Knox Co., Johnstown, New York1
- Charles B. Knox Gelatine Co., Inc, Johnstown, New York1
- Charles B. Knox Gelatine Co., Inc, Johnstown, New York;1
- Charles B. Knox Gelatine Co., Inc.1
- Charles B. Knox Gelatine Co., Inc., Johnstown, New York, Montreal, Canada1
- Charles Gulden, Inc.1
- Charleston County Register Mesne Conveyance1
- Chester County Historical Society Archives697
- Chester County Historical Society Archives (S.C.)4,352
- Chester County Historical Society. Chester County (S.C.)204