Knoxville is a city located in Marion County Iowa. It is also the county seat of Marion County. With a 2020 population of 7,116, it is the 58th largest city in Iowa and the 3925th largest city in the United States . Knoxville is currently declining at a rate of -0.36% annually and its population has decreased by -2.69% since the most recent census, which recorded a population of 7,313 in 2010. Knoxville reached it's highest population of in . Spanning over 5 miles, Knoxville has a population density of 1,538 people per square mile.
The average household income in Knoxville is $59,488 with a poverty rate of 14.93%. The median rental costs in recent years comes to $672 per month, and the median house value is $95,100. The median age in Knoxville is 40.9 years, 40.5 years for males, and 42.1 years for females.