Oskaloosa is a city located in Mahaska County Iowa. It is also the county seat of Mahaska County. With a 2020 population of 11,622, it is the 34th largest city in Iowa and the 2791st largest city in the United States . Oskaloosa is currently growing at a rate of 0.50% annually and its population has increased by 1.39% since the most recent census, which recorded a population of 11,463 in 2010. Oskaloosa reached it's highest population of in . Spanning over 8 miles, Oskaloosa has a population density of 1,449 people per square mile.
The average household income in Oskaloosa is $63,159 with a poverty rate of 20.08%. The median rental costs in recent years comes to $653 per month, and the median house value is $96,300. The median age in Oskaloosa is 35 years, 31.6 years for males, and 38.1 years for females.