Shelbyville
- County:
- Shelby County
- County Seat:
- Yes
- Area (mi²):
- 4.085
- State:
- Illinois
Shelbyville is a city located in Shelby County, Illinois. Shelbyville has a 2026 population of 4,540. It is also the county seat of Shelby County. Shelbyville is currently declining at a rate of -0.61% annually and its population has decreased by -2.37% since the most recent census, which recorded a population of 4,650 in 2020.