| Carlin | Unisex | Irish Names |
| Carlow | Man | Irish Names |
| Carr | Man | Irish Names |
| Carrigan | Unisex | Irish Names |
| Casey | Unisex | Irish Names |
| Cashel | Man | Irish Names |
| Cassidy | Unisex | Irish Names |
| Cathair | Man | Irish Names |
| Cathal | Man | Irish Names |
| Cathán | Man | Irish Names |
| Cathleen | Woman | Irish Names |
| Cavan | Man | Irish Names |
| Cayleen | Woman | Irish Names |
| Ceallach | Man | Irish Names |
| Ceara | Woman | Irish Names |
| Chevonne | Woman | Irish Names |
| Cian | Man | Irish Names |
| Cianna | Woman | Irish Names |
| Ciar | Man | Irish Names |
| Ciara | Woman | Irish Names |