- Carno
- Carrog
- Carway
- Cascob
- Casnewydd
- Castle Caereinion
- Castlemartin
- Castlemorris
- Cathedine
- Cefn-coed-y-cymmer
- Cefn Cribwr
- Cefn-y-bedd
- Cefn-y-pant
- Cefneithin
- Cellan
- Cemaes Bay
- Cemmaes
- Cemmaes Road
- Cenarth
- Cerrig-y-Druidion
- Chepstow
- Chirk
- Church Stoke
- Chwilog
- Cilcain
- Cilcennin
- Cilgerran
- Cilgwm
- Ciliau-Aeron
- Cilrhedyn