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. By 1843, settlers began moving here. The first Marion County Courthouse was erected three years later.