- Camano
- Camas
- Canterwood
- Carbonado
- Carlsborg
- Carnation
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- Cascade Valley
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- Castle Rock
- Cathan
- Cathcart
- Cathlamet
- Centerville
- Central Park
- Centralia
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- Chehalis Village
- Chelan
- Chelan Falls
- Cheney
- Cherry Grove
- Chewelah
- Chico
- Chinook
- City of Sammamish
- Clallam Bay
- Clarkston
- Clarkston Heights-Vineland
- Cle Elum
- Clear Lake
- Clearview
- Cliffdell
- Clinton
- Clyde Hill
- Cohassett Beach
- Colfax
- College Place
- Colton
- Colville
- Conconully
- Concrete
- Connell
- Conway
- Copalis Beach
- Cosmopolis
- Cottage Lake
- Coulee City
- Coulee Dam
- Country Homes
- Coupeville
- Covington
- Cowiche
- Creston
- Crocker
- Crystal Mountain
- Curlew
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- Custer
- Custer
