C
- (Sligo) Colgagh
- (County Galway) Clynagh Island
- (Roscommon) Clydagh
- (Mayo County) Cloonslaun
- (Mayo County) Cloonmore
- (Roscommon) Cloonmore
- (Mayo County) Cloonlavis
- (Roscommon) Cloonkeen
- (Mayo County) Cloongowla
- (Roscommon) Cloonfower
- (Roscommon) Clooneen
- (County Galway) Clooneen
- (County Leitrim) Cloone
- (County Galway) Cloondergan
- (Roscommon) Clooncah
- (Roscommon) Clooncah
- (Roscommon) Cloonakilleg
- (Sligo) Cloonacool
- (County Galway) Clonfert
- (County Galway) Clonbern
- (Mayo County) Cloghmore
- (Mayo County) Clogher
- (Mayo County) Clogher
- (Mayo County) Clogher
- (County Galway) Cleggan
- (Mayo County) Clare Island
- (County Galway) Claggan
- (County Galway) Claddagh
- (Mayo County) Church Village
- (Roscommon) Cavetown