| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 221 | Carroll | Irish | Manly. | M | |
| 222 | Cartagh | Irish | Variant of Carthach: Loving. A variant of Caradoc. The Irish St. Carthach, also known as St Carthage, founded an early 7th century monastery at Lismore, County Waterford. | M | |
| 223 | Carthach | Irish | Loving. A variant of Caradoc. The Irish St. Carthach, also known as St Carthage, founded an early 7th century monastery at Lismore, County Waterford. | M | |
| 224 | Carthage | Irish | Variant of Carthach: Loving. | M | |
| 225 | Cary | Irish | Of the dark ones. | M | |
| 226 | Case | Irish | Variant of Casey: Observant; alert; vigorous. | M | |
| 227 | Casey | Irish | Observant; alert; vigorous. Famous Bearer: radio personality and voice of 'Scooby-Doo' (cartoon dog) Casey Kasem. | M | |
| 228 | Cashel | Irish | From Cashel. | M | |
| 229 | Cass | Irish | Curly-headed. | M | |
| 230 | Cassady | Irish | Variant of Cassidy: Intelligent; from Caiside; curly-headed. | M | |
| 231 | Cassian | Irish | Curly-headed. | M | |
| 232 | Cassidy | Irish | Intelligent; from Caiside; curly-headed. | M | |
| 233 | Cathal | Irish | Battle strong. | M | |
| 234 | Cathall | Irish | Ready for war. | M | |
| 235 | Cathaoir | Irish | Variant of Cahir: Warrior. | M | |
| 236 | Cathmor | Irish | Great fighter. | M | |
| 237 | Cathmore | Irish | Great fighter. | M | |
| 238 | Caulan | Irish | Variant of Caelan: Powerful warrior. | M | |
| 239 | Cavan | Irish | Good-looking; handsome; from Cavan. | M | |
| 240 | Cayce | Irish | Variant of Casey: Observant; alert; vigorous. | M | |