- Scotia
- Scott
- Scotton Corner
- Scout Island
- Scribner
- Sea Acre
- Sea Breeze Mobile Home Park
- Sea Lion Rock
- Sea Lion Rock
- Seabeck
- Seabird Mobile Home Park
- Seabold
- Seahurst
- Seal Rock
- SeaTac
- Seatons Grove
- Seattle
- Seattle Heights
- Seattle Hill
- Seattle Hill-Silver Firs
- Seaview
- Secar Rock
- Sedro-Woolley
- Sekiu
- Selah
- Selfs Trailer Park
- Selleck
- Seltice
- Semiahmoo
- Sentinel Island