| Abbreviation | Definition |
|---|---|
| CLNHA | Crater Lake Natural History Association (est. 1942) |
| CLUTCH | Computer Literacy Understanding Through Community History |
| CMHG | Canadian Military History Gateway |
| CMHG | Colorado Military Historical Group |
| CMNH | Carnegie Museum of Natural History |
| CMNH | Cleveland Museum of Natural History |
| CMTRY | Cemetry |
| CNHA | Canyonlands Natural History Association |
| CNHA | Chincoteague Natural History Association |
| CNHH | Canadian Network on Humanitarian History |
| COHA | Canadian Oral History Association |
| COHR | Center for Oral History Research |
| COHT | Centre for Oral History and Tradition |
| COHT | Centre for Oral History Tradition |
| COHT | Coalition Of Historical Trekkers |
| COHT | Credit Opinion History Tables |
| CPH | Center for Presidential History |
| CPHA | Center for Public History and Archaeology |
| CPHC | Centre for Printing History and Culture |
| CPHD | California Pioneer History Days |