C
- (County Leitrim) Carrickmurray
- (County Leitrim) Corderry
- (County Leitrim) Corrasra
- (County Leitrim) Corratimore Glebe
- (Roscommon) Carrowbaun
- (Roscommon) Clooncruffer
- (Roscommon) Cuiltaboolia
- (Roscommon) Cornagrea
- (Roscommon) Cornamucklagh
- (Sligo) Carrigeenboy
- (Sligo) Creevagh
- (Sligo) Carricknagrip
- (Sligo) Coolmurly
- (Sligo) Carricknagat
- (Sligo) Crockalaghta
- (County Galway) Cinn an Bhaile
- (County Galway) Ceantar na nOileán
- (Mayo County) Cabin River
- (Sligo) Curry
- (County Galway) Curragh West
- (Roscommon) Curraghaleen
- (County Galway) Curragh
- (County Galway) Cur
- (Sligo) Culleens
- (Mayo County) Cuilmullagh
- (Mayo County) Cuilmore
- (County Galway) Crump Island
- (County Galway) Crumpaun
- (County Galway) Cruagh
- (County Galway) Crosswell