C
- (Mayo County) Clooncullenbaun
- (Mayo County) Carrowkeeran
- (Mayo County) Cloonagh
- (Mayo County) Carricknacally
- (Mayo County) Carrigeen
- (Mayo County) Cloonkeen
- (Mayo County) Creggaunnahorna
- (Mayo County) Cranareen
- (Mayo County) Coolbarreen
- (Mayo County) Carrowbeg
- (Mayo County) Carrowgarve
- (Mayo County) Coiladussaun
- (Mayo County) Cliff Island
- (Mayo County) Cuingbeg
- (Mayo County) Curragh
- (Mayo County) Clossaghroe
- (Mayo County) Cornanaff
- (Mayo County) Carrownacross
- (Mayo County) Carroward
- (Mayo County) Castle Island
- (Mayo County) Cabragh
- (Mayo County) Cashel
- (Mayo County) Cummauns
- (Mayo County) Claggarnagh West
- (Mayo County) Claggarnagh East
- (Mayo County) Clooneshil
- (Mayo County) Cloondacon
- (Mayo County) Cloontubbrid
- (Mayo County) Cunnacher
- (Mayo County) Cloonagleragh