- Copalis Beach
- Cosmopolis
- Cottage Lake
- Coulee City
- Coulee Dam
- Country Homes
- Coupeville
- Creston
- Cusick
- Custer
- Camas
- Castle Rock
- Colton
- Conway
- Covington
- Custer
- Clinton
- Coffee Pot Island
- Coyote Islands (historical)
- Cabin Creek
- Cactus
- Cactus Island
- Cactus Islands
- Cakesosta
- Caledonia
- Calhounville
- Calispell
- Calmor Cove Club Mobile Home Park
- Camano Island
- Camas