C
- (Renfrew County) Calabogie
- Caledon
- Cobalt
- Cochrane
- (Durham) Clarington
- (Northumberland County) Castleton
- (Durham) Cadmus
- (United Counties of Leeds and Grenville) Caintown
- (Middlesex County) Cairngorm
- (Lambton County) Cairo
- (Regional Municipality of Niagara) Caistor Centre
- (Regional Municipality of Niagara) Caistorville
- (Grey County) Calderwood
- (Haldimand County) Caledonia
- (United Counties of Leeds and Grenville) California
- (Lanark County) California
- (Kenora District) Caliper Lake
- (Nipissing District) Callander
- (Elgin County) Calton
- (Renfrew County) Camel Chute
- (Regional Municipality of Niagara) Camelot Beach
- (Peterborough County) Cameron
- (Dufferin County) Campania
- (United Counties of Leeds and Grenville) Campbells Corners
- (Elgin County) Campbellton
- (Peterborough County) Campbelltown
- (Cochrane District) Camp Island
- (Frontenac County) Camp Oconto
- (Elgin County) Candyville
- (Oxford County) Canning