- Cloonsheecahill
- Cloonymorris
- Cloosh
- Clybaun
- Clydagh
- Clynagh Island
- Coarsefield
- Coldwood
- Colmanstown
- Connagh
- Coogla
- Coolacurn
- Coolagh
- Coolagh
- Coolpowra
- Corballymore
- Corboley
- Cornamona
- Cornamucklagh
- Corraduff
- Corrafaireen
- Corrandulla
- Corranellistrum
- Corrantarramul
- Corrofin
- Corrúch
- Corskeagh
- Costelloe
- Coteeny
- Coxtown