Shelby County, Illinois

Shelby County, Illinois
Location within the U.S. state of Illinois
Coordinates: 39°23′N 88°49′W / 39.39°N 88.81°W / 39.39; -88.81
Country United States
State Illinois
Founded1827
Named afterIsaac Shelby
SeatShelbyville
Largest cityShelbyville
Area
 • Total
768 sq mi (1,990 km2)
 • Land759 sq mi (1,970 km2)
 • Water9.5 sq mi (25 km2)  1.2%
Population
 (2020)
 • Total
20,990
 • Estimate 
(2024)
20,542
 • Density27.7/sq mi (10.7/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Congressional district15th
Websitewww.shelbycounty-il.com

Shelby County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 20,990. Its county seat is Shelbyville.