C
- (Uíbh Fhailí) Clonavoe
- (Kilkenny) Clonamery
- (Wexford) Clohamon
- (Fingal County) Cloughran
- (Meath) Clogherstown
- (Westmeath) Cloghan
- (Wexford) Clogh
- (An Longfort) Cleraun
- (Laois) Cleanagh
- (An Longfort) Clawinch
- (County Carlow) Clashganna Bridge
- (Uíbh Fhailí) Clareen
- (Wicklow) Clara Bridge
- (Wicklow) Clara
- (Westmeath) Churchtown
- (Wexford) Churchtown
- (Wexford) Churchtown
- (Uíbh Fhailí) Charlestown
- (Fingal County) Chapelmidway
- (Wexford) Chapel
- (Kilkenny) Castlewarren
- (Kildare) Castletown
- (Louth) Castle Roche Cross Roads
- (Meath) Castlejordan
- (Wexford) Castledockrell
- (Meath) Castlecor
- (Kildare) Carton
- (Dún Laoghaire-Rathdown) Carrickmines
- (An Longfort) Carrickboy
- (Wexford) Carrick