C
- (Mayo County) Camport
- (Roscommon) Caltragh
- (County Galway) Caltra
- (Mayo County) Callow
- (County Galway) Caherlistrane
- (Mayo County) Caher Island
- (County Galway) Caher
- (Sligo) Cabraghkeel
- (County Galway) Claddaghduff
- (County Galway) Cashleen
- (Mayo County) Cushlecka
- (Mayo County) Cashel
- (Mayo County) Corclogh
- (County Leitrim) Clooncose
- (Mayo County) Cloonfinnaun
- (Mayo County) Cloongullaun
- (Mayo County) Carroweeny
- (Mayo County) Carrowmore
- (Mayo County) Cloonarannana Bridge
- (Mayo County) Cloonlara
- (Mayo County) Cloonaghboy
- (Mayo County) Creggaun
- (Mayo County) Cloonfinish
- (Mayo County) Cloonmeen West
- (Mayo County) Cloontia
- (Mayo County) Cloonlarhan
- (Mayo County) Carrownaglogh
- (Roscommon) Cloonlumney
- (Roscommon) Cuppanagh Bridge
- (Roscommon) Cornaglia