| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 161 | Cnychwr | Welsh | Legendary son of Nes. | M | |
| 162 | Coch | Welsh | Legendary son of Caw. | M | |
| 163 | Coed | Welsh | Dwells in the woods. | M | |
| 164 | Colwin | Welsh | Variant of Colwyn: Name of a river in Wales. | M | |
| 165 | Colwyn | Welsh | Name of a river in Wales. | M | |
| 166 | Colywnn | Welsh | Variant of Colwyn: Name of a river in Wales. | M | |
| 167 | Conway | Welsh | Holy river. Place-name and surname. | M | |
| 168 | Conwy | Welsh | Variant of Conway: Holy river. Place-name and surname. | M | |
| 169 | Conyn | Welsh | Legendary son of Caw 'wise'. | M | |
| 170 | Craddock | Welsh | Affection; beloved. | M | |
| 171 | Cradoe | Welsh | Beloved. | M | |
| 172 | Craig | Welsh | Rock. | M | |
| 173 | Crist | Welsh | Christian. | M | |
| 174 | Cubert | Welsh | Legendary son of Daere. | M | |
| 175 | Culhwch | Welsh | Legendary son of K;Iydd. | M | |
| 176 | Culvanawd | Welsh | Legendary son of GwIyon. | M | |
| 177 | Custenhin | Welsh | Legendary father of Erbin. | M | |
| 178 | Cwrig | Welsh | Master. | M | |
| 179 | Cymry | Welsh | From Wales. | M | |
| 180 | Cynan | Welsh | Chief. | M | |