- Cabinteely
- Cabra
- Cabragh
- Caher
- Caherconlish
- Cahersiveen
- Callan
- Calverstown
- Camolin
- Campile
- Cappamore
- Cappawhite
- Cappoquin
- Carlanstown
- Carlingford
- Carlow
- Carndonagh
- Carnew
- Carney
- Carragh
- Carraroe
- Carrick
- Carrick on Shannon
- Carrick-on-Suir
- Carrickart
- Carrickmacross
- Carrigaline
- Carrigallen
- Carrigans
- Carrigkerry
- Carrignavar
- Carrigtohill
- Carrowkeel
- Cashel
- Castlebar
- Castlebellingham
- Castleblayney
- Castlebridge
- Castlecomer
- Castleconnell
- Castledermot
- Castleellis
- Castlefin
- Castlegregory
- Castleisland
- Castleknock
- Castlelyons
- Castlemaine
- Castlemartyr
- Castlepollard
- Castlerea
- Castletown
- Castletown
- Castletown Geoghegan
- Castletownbere
- Castletownroche
- Castletownshend
- Causeway
- Cavan
- Celbridge
- Chapelizod
- Chapeltown
- Charlesland
- Charlestown
- Cheekpoint
- Cherry Orchard
- Cherryville
- Churchbay
- Churchtown
- Clane
- Clara
- Claregalway
- Claremorris
- Clarina
- Clarinbridge
- Clashmore
- Clifden
- Cliffony
- Clogh
- Cloghan
- Clogheen
- Clogherhead
- Cloghjordan
- Clonakilty
- Clonard
- Clonaslee
- Clonbullogue
- Clondalkin
- Clondrohid
- Clondulane
- Clonee
- Clonegall
- Clones
- Clonlara
- Clonmany
- Clonmel
- Clonmellon
- Clonroche
- Clonskeagh
- Clonygowan
- Cloonboo
- Cloonfad
- Cloontuskert
- Cloughduv
- Cloyne
- Coachford
- Collinstown
- Collon
- Collooney
- Commons
- Confey
- Cong
- Conna
- Convoy
- Coolagary
- Coolaney
- Coolboy
- Coolgreany
- Coolock
- Cootehill
- Cork
- Corrofin
- Corrofin
- Courtmacsherry
- Courtown
- Cratloe
- Craughwell
- Creeslough
- Croagh
- Crocknamurleog
- Cromane
- Crookstown
- Croom
- Cross Barry
- Crossakeel
- Crosshaven
- Crossmolina
- Crumlin
- Crusheen
- Culdaff
