| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 161 | Condan | Celtic | Dark haired wise man. | M | |
| 162 | Condon | Celtic | Dark haired wise man. | M | |
| 163 | Conn | Celtic | Mythical son of Lir: wise; High; mighty. | M | |
| 164 | Connal | Celtic | 'High; mighty.'. | M | |
| 165 | Connell | Celtic | Strong in battle. | M | |
| 166 | Connla | Celtic | Mythical son of Conn. | M | |
| 167 | Conroy | Celtic | Persistent. | M | |
| 168 | Conway | Celtic | Hound of the plain. | M | |
| 169 | Corann | Celtic | Mythical druid. | M | |
| 170 | Cormac | Celtic | Charioteer. | M | |
| 171 | Cradawg | Celtic | Mythical son of Bran. | M | |
| 172 | Cuchulain | Celtic | Mythical Hound of Ulster. | M | |
| 173 | Cuinn | Celtic | Wise. | M | |
| 174 | Culain | Celtic | Mythical smith. | M | |
| 175 | Culann | Celtic | Mythical smith. | M | |
| 176 | Cullen | Celtic | Cub. | M | |
| 177 | Custennin | Celtic | Mythical giant. | M | |
| 178 | Dallas | Celtic | Dwells by the waterfall. | M | |
| 179 | Daman | Celtic | Demon. | M | |
| 180 | Darcy | Celtic | Dark. | M | |