Knoxville is a city in Marion County, Iowa, United States. The population was 7,313 at the 2010 census, a decrease from 7,731 in the 2000 census. It is the county seat of Marion County. Knoxville is home of the National Sprint Car Hall of Fame & Museum, located next to the famous Knoxville Raceway dirt track.
The site for the future county seat of Marion County was selected because it was within a mile of the geographic center of the county, reasonably level and near a good source of timber.
Knoxville is located in south-central Iowa, some 35 miles southeast of Des Moines. The area was originally inhabited by Native Americans of the Sac and Fox tribes. At that time, prairie grass covered the countryside at heights of 8 to 10 feet. In 1835, Dragoons first explored the Des Moines River valley through this area. In 1842, the Sac and Fox Indians signed a treaty to sell lands in central Iowa to the new settlers known as the New Purchase of 1842.