- Coffee Pot Island
- Coyote Islands (historical)
- Cabin Creek
- Cactus
- Cactus Island
- Cactus Islands
- Cakesosta
- Caledonia
- Calhounville
- Calispell
- Calmor Cove Club Mobile Home Park
- Camano
- Camano Island
- Camas
- Camas
- Camden
- Camelot Mobile Estates
- Camelot Square Mobile Home Park
- Camp Diana
- Camp Discovery
- Camp Orkila
- Campton
- Canada Island
- Canby
- Candlewood Estates Mobile Home Park
- Canoe
- Canoe Island
- Canterbury Square Mobile Home Park
- Canterwood
- Canyon Glen Mobile Home Park