| Claebourn | A variant meaning dweller by the clay brook. |
| Claeburn | Dweller by the clay brook |
| Claeton | From the town of clay soil |
| Clai | A variant of the name Clay |
| Claiburn | One from the clay boundary |
| Claiburne | Dweller near clay stream |
| Claiton | From the town of clay land |
| Claretta | A small, clear, and bright soul. |
| Clarity | The quality of being very clear. |
| Claudie | A diminutive form of Claudia. |
| Claybourn | Dweller near the clay brook. |
| Clayd | A variant spelling of Clyde. |
| Claytan | A variant spelling of Clayton. |
| Clenton | From the town on the hillside. |
| Cliffeton | From the town by the cliff. |
| Clifftan | Dweller near the steep cliff. |
| Clifften | One from the cliff settlement. |
| Cliffy | A diminutive of cliff dweller. |
| Cliften | From the farm by the cliff. |
| Clindon | From the hill near the cliff. |
| Clintan | Dweller of the stony settlement. |
| Clinten | One from the rocky enclosure. |
| Clintin | From the settlement on a hill. |
| Cloud | Named after the fluffy sky vapor. |
| Clova | A name meaning a field of clover. |
| Clyndon | From the hill of the famous. |
| Clyntan | Derived from a settlement near a hill. |
| Clynten | Variant meaning town by the hill. |
| Clynton | Old English for town on a hill. |
| Clyntwood | A forest located near a cliff. |
| Coal | Refers to the black mineral fuel. |
| Coale | An archaic spelling for charcoal. |
| Cobe | A variant of the name Jacob or Jake. |
| Cobey | A variant of the name Colby. |
| Colbie | A form of colby |
| Coline | A French variant of Nicole. |
| Colmann | A variant of the name Colman. |
| Colte | A name meaning young horse. |
| Commodore | A title meaning a naval commander. |
| Cortnee | An English name meaning the courtly. |