- Skylark Village Mobile Home Park
- Skyway
- Slater
- Sleepy Hollow
- Small Island
- Smelter Rock
- Smith Island
- Smith Island
- Smith Place
- Smithville
- Smokey Point
- Smokey Point (historical)
- Smyrna
- Snag Islands
- Snake River
- Snee Oosh
- Snohomish
- Snoose Junction
- Snoqualmie
- Snoqualmie Falls
- Snoqualmie Pass
- Snoquera
- Snowden
- Snug Harbor
- Snug Harbor Mobile Home Park
- Snug Harbor Mobile Home Park
- Snyders Corner
- Soap Lake
- Sobey
- Sokulk