| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Illahee | city | Washington | United States | 47.61 | -122.60 | 59 | |
| Illia | city | Washington | United States | 46.68 | -117.50 | 984 | |
| Ilwaco | city | Washington | United States | 46.31 | -124.04 | 0 | |
| Image | city | Washington | United States | 45.61 | -122.58 | 200 | |
| Impach | city | Washington | United States | 48.29 | -118.24 | 1797 | |
| Inchelium | city | Washington | United States | 48.30 | -118.20 | 1669 | |
| Independence | city | Washington | United States | 46.80 | -123.16 | 183 | |
| Index | city | Washington | United States | 47.82 | -121.56 | 1174 | |
| Indian Beach | city | Washington | United States | 48.16 | -122.52 | 32 | |
| Indian Village | city | Washington | United States | 48.57 | -122.65 | 111 | |
| Indian Village Mobile Home Park | city | Washington | United States | 46.20 | -123.37 | 288 | |
| Indianola | city | Washington | United States | 47.75 | -122.53 | 0 | |
| Inglesea | city | Washington | United States | 47.49 | -122.36 | 357 | |
| Inglewood | city | Washington | United States | 47.73 | -122.23 | 400 | |
| Inglewood | city | Washington | United States | 47.62 | -122.07 | 347 | |
| Inglewood Estates Mobile Home Park | city | Washington | United States | 47.76 | -122.24 | 157 | |
| Interbay | city | Washington | United States | 47.64 | -122.40 | 190 | |
| Intercity | city | Washington | United States | 47.91 | -122.24 | 830 | |
| Interlaken | city | Washington | United States | 47.16 | -122.54 | 285 | |
| Ione | city | Washington | United States | 48.74 | -117.42 | 1998 | |
| Irby | city | Washington | United States | 47.36 | -118.85 | 1669 | |
| Ireland | city | Washington | United States | 45.66 | -122.37 | 830 | |
| Iron Springs | city | Washington | United States | 47.16 | -124.19 | 32 | |
| Irondale | city | Washington | United States | 48.04 | -122.77 | 154 | |
| Irwin | city | Washington | United States | 47.69 | -117.24 | 2040 | |
| Island Park Manufactured Home Park | city | Washington | United States | 48.33 | -122.61 | 144 | |
| Island View | city | Washington | United States | 46.24 | -119.22 | 357 | |
| Islandale | city | Washington | United States | 48.45 | -122.86 | 19 | |
| Islander Mobile Home Park | city | Washington | United States | 47.63 | -122.52 | 0 | |
| Issaquah | city | Washington | United States | 47.53 | -122.03 | 200 |