| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 221 | Caradoc | Celtic | Dearly loved. | M | |
| 222 | Carbry | Celtic | Charioteer. | M | |
| 223 | Cardew | Celtic | From the black fort. | M | |
| 224 | Carew | Celtic | From the fortress. | M | |
| 225 | Carey | Celtic | The dark one. | F | |
| 226 | Carey | Celtic | From the fortress. | M | |
| 227 | Carmel | Celtic | From the vinyard. | F | |
| 228 | Carney | Celtic | Fighter. | M | |
| 229 | Carr | Celtic | Fighter. | M | |
| 230 | Carrington | Celtic | Place name and surname. | M | |
| 231 | Carrol | Celtic | Champion. | M | |
| 232 | Carroll | Celtic | Champion. | M | |
| 233 | Cary | Celtic | The dark one. | F | |
| 234 | Cary | Celtic | From the fortress. | M | |
| 235 | Casey | Celtic | Brave. | M | |
| 236 | Cassivellaunus | Celtic | From Arthurian legend. | M | |
| 237 | Caswallan | Celtic | From Arthurian legend. | M | |
| 238 | Cathair | Celtic | Fighter. | M | |
| 239 | Cathal | Celtic | Strong in battle. | M | |
| 240 | Cathaoir | Celtic | Fighter. | M | |