| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Sea Acre | city | Washington | United States | 48.65 | -122.76 | 0 | |
| Sea Breeze Mobile Home Park | city | Washington | United States | 48.10 | -122.79 | 0 | |
| SeaTac | city | Washington | United States | 47.45 | -122.32 | 295 | |
| Seabeck | city | Washington | United States | 47.64 | -122.83 | 239 | |
| Seabird Mobile Home Park | city | Washington | United States | 47.74 | -122.64 | 95 | |
| Seabold | city | Washington | United States | 47.70 | -122.56 | 98 | |
| Seahaven (historical) | city | Washington | United States | 46.69 | -123.82 | 3 | |
| Seahurst | city | Washington | United States | 47.47 | -122.36 | 298 | |
| Seal Rock | city | Washington | United States | 47.71 | -122.89 | 0 | |
| Seaport (historical) | city | Washington | United States | 46.60 | -123.95 | 0 | |
| Seatlo | city | Washington | United States | 47.61 | -122.33 | 196 | |
| Seatons Grove | city | Washington | United States | 48.02 | -118.95 | 1669 | |
| Seattle | city | Washington | United States | 47.61 | -122.33 | 196 | |
| Seattle Heights | city | Washington | United States | 47.81 | -122.32 | 400 | |
| Seattle Heights Mobile Home Park | city | Washington | United States | 47.81 | -122.33 | 400 | |
| Seattle Hill | city | Washington | United States | 47.88 | -122.16 | 403 | |
| Seattlum | city | Washington | United States | 47.61 | -122.33 | 196 | |
| Seaview | city | Washington | United States | 46.33 | -124.05 | 9 | |
| Sedro-Woolley | city | Washington | United States | 48.50 | -122.24 | 75 | |
| Sekiu | city | Washington | United States | 48.26 | -124.30 | 272 | |
| Selah | city | Washington | United States | 46.65 | -120.53 | 1197 | |
| Selfs Trailer Park | city | Washington | United States | 47.51 | -120.43 | 830 | |
| Selleck | city | Washington | United States | 47.38 | -121.87 | 1233 | |
| Seltice | city | Washington | United States | 47.16 | -117.09 | 2598 | |
| Semiahmoo | city | Washington | United States | 48.99 | -122.77 | 0 | |
| Seola Beach | city | Washington | United States | 47.49 | -122.37 | 0 | |
| Sequim | city | Washington | United States | 48.08 | -123.10 | 154 | |
| Sequim West Mobile Home Park | city | Washington | United States | 48.08 | -123.12 | 209 | |
| Serene | city | Washington | United States | 47.87 | -122.30 | 830 | |
| Serene Terrace Mobile Home Park | city | Washington | United States | 47.87 | -122.27 | 830 | |
| Servia | city | Washington | United States | 46.92 | -118.75 | 1669 | |
| Seven Bays | city | Washington | United States | 47.85 | -118.34 | 1669 | |
| Seven Lakes Mobile Home Park | city | Washington | United States | 48.16 | -122.27 | 830 | |
| Seven Mile | city | Washington | United States | 47.74 | -117.51 | 1669 | |
| Seward Park | city | Washington | United States | 47.55 | -122.26 | 3 |