Rock Valley
- County:
- Sioux County
- County Seat:
- No
- Area (mi²):
- 4.461
- State:
- Iowa
Rock Valley is a city located in Sioux County, Iowa. Rock Valley has a 2026 population of 4,024. Rock Valley is currently declining at a rate of -0.45% annually and its population has decreased by -1.2% since the most recent census, which recorded a population of 4,073 in 2020.