Knoxville
- County:
- Marion County
- County Seat:
- Yes
- Area (mi²):
- 4.618
- State:
- Iowa
Knoxville is a city located in Marion County, Iowa. Knoxville has a 2026 population of 7,440. It is also the county seat of Marion County. Knoxville is currently growing at a rate of 0.24% annually but its population has decreased by -1.77% since the most recent census, which recorded a population of 7,574 in 2020.