Onawa is a city located in Monona County Iowa. It is also the county seat of Monona County. With a 2020 population of 2,726, it is the 122nd largest city in Iowa and the 6547th largest city in the United States . Onawa is currently declining at a rate of -0.69% annually and its population has decreased by -9.07% since the most recent census, which recorded a population of 2,998 in 2010. Onawa reached it's highest population of 3,498 in 1950. Spanning over 5 miles, Onawa has a population density of 525 people per square mile.
The average household income in Onawa is $50,536 with a poverty rate of 25.10%. The median rental costs in recent years comes to $611 per month, and the median house value is $83,900. The median age in Onawa is 41.7 years, 37.7 years for males, and 46.8 years for females.