C
- (Mayo County) Carrick
- (Mayo County) Carricknaweeloge
- (Mayo County) Cloghbrack
- (Mayo County) Carrownaglogh
- (Mayo County) Carrowkeel
- (Mayo County) Cartur Ghilbeirt
- (Mayo County) Carrigeenmore
- (Mayo County) Cartron
- (Mayo County) Coimin na Croise
- (Mayo County) Carricknaroun
- (Mayo County) Cross Rock
- (Mayo County) Carricknaronty
- (Mayo County) Carricknaronty North
- (Mayo County) Carrigeenmore
- (Mayo County) Curlew Hill
- (Mayo County) Curraghboy
- (Mayo County) Cong
- (Roscommon) Cootehall
- (Roscommon) Cloontuskert
- (Roscommon) Cloonfad
- (County Galway) Cloonboo
- (County Leitrim) Carrigallen
- (County Galway) Clarinbridge
- (Sligo) Carney
- (Sligo) Cliffony
- (County Galway) Corrofin
- (County Galway) Craughwell
- (County Galway) Carraroe
- (Sligo) Coolaney
- (Mayo County) Charlestown