- Castleisland
- Castlemaine
- Castlequarter
- Castlequin
- Castleshannon
- Casttercose
- Causeway
- Chapeltown
- Chapeltown
- Churchtown
- Clahane
- Clash
- Clashlehane Bridge
- Clashmelcon
- Cleady
- Cleanderry
- Cliddaun
- Clieveagh
- Cloghane
- Cloghane
- Cloghanebane
- Cloghaneleesh
- Cloghanenagleragh
- Cloghaun
- Clogher
- Clogher
- Cloghvoola
- Clondouglas
- Cloonagh Bridge
- Cloonaman