Monmouth
- County:
- Jackson County
- County Seat:
- No
- Area (mi²):
- 0.569
- State:
- Iowa
Monmouth is a city located in Jackson County, Iowa. Monmouth has a 2026 population of 129. Monmouth is currently declining at a rate of 0% annually and its population has decreased by 0% since the most recent census, which recorded a population of 129 in 2020.