- South Finger Island
- South Peapod
- Saddle Dam Campground
- Saddlebag Island
- Saddleview Mobile Home Park
- Sagemoor
- Saginaw
- Sahalee
- Saint Andrews
- Saint Clair
- Saint Cloud
- Saint Helens
- Saint John
- Saint John
- Saint Martins Hot Springs
- Saint Urban
- Salkum
- Salmon Creek
- Samish
- Samish Island
- Sammamish
- Sampson
- Sams Trailer Park
- San de Fuca
- Isla San Juan
- San Juan Islands
- San Souci Mobile Estates
- Sand - Lo Trailer Park
- Sand Island
- Sand Island