| Ceara | Woman | Irish Names |
| Chevonne | Woman | Irish Names |
| Cian | Man | Irish Names |
| Cianna | Woman | Irish Names |
| Ciar | Man | Irish Names |
| Ciara | Woman | Irish Names |
| Ciaran | Man | Irish Names |
| Cillian | Man | Irish Names |
| Ciniod | Man | Irish Names |
| Clancy | Man | Irish Names |
| Clidhna | Woman | Irish Names |
| Cliona | Woman | Irish Names |
| Clodagh | Woman | Irish Names |
| Coffey | Unisex | Irish Names |
| Colm | Man | Irish Names |
| Colum | Man | Irish Names |
| Comiskey | Unisex | Irish Names |
| Conan | Man | Irish Names |
| Conary | Unisex | Irish Names |
| Conlan | Man | Irish Names |