Rock Island
- County:
- Douglas County
- County Seat:
- No
- Area (mi²):
- 1.127
- State:
- Washington
Rock Island is a city located in Douglas County, Washington. Rock Island has a 2026 population of 1,722. Rock Island is currently growing at a rate of 6.03% annually and its population has increased by 33.59% since the most recent census, which recorded a population of 1,289 in 2020.