Eureka
- County:
- Adair County
- County Seat:
- No
- Area (mi²):
- 35.569
- State:
- Iowa
Eureka is located in Adair County, Iowa. Eureka has a 2025 population of 29 . Eureka 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 0 in 2020.
The median age in Eureka is 50.2 years: 0 years for males, and 0 years for females. For every 100 females there are 141.7 males.