C
- (Mayo County) Cappavicar North
- (Mayo County) Coolshinnagh
- (Mayo County) Carrowcastle
- (Mayo County) Cloonconra
- (Mayo County) Cregnafyla
- (Mayo County) Cloonmung
- (Mayo County) Corlummin
- (Mayo County) Cullin
- (Mayo County) Corlee
- (Mayo County) Cloghans
- (Mayo County) Carrowntreila
- (Mayo County) Cooleran
- (Mayo County) Corimla
- (Mayo County) Cloonta
- (Mayo County) Carrower
- (Sligo) Cabragh
- (Sligo) Carranduff
- (Sligo) Carrowhubbuck
- (Sligo) Carraun
- (Mayo County) Castle Island
- (Mayo County) Cragh Islands
- (Mayo County) Castlehill
- (Mayo County) Cum
- (Mayo County) Corcullin
- (Mayo County) Croaghaun
- (Mayo County) Cloontakilla
- (Mayo County) Carrickmoylenacurhoga
- (Mayo County) Clooneen
- (Mayo County) Carrickhesk
- (Mayo County) Cluddaun