Johnson County | |
---|---|
![]() Johnson County Courthouse in Vienna | |
![]() Location within the U.S. state of Illinois | |
![]() Illinois's location within the U.S. | |
Coordinates: 37°28′N 88°52′W / 37.46°N 88.87°W | |
Country | ![]() |
State | ![]() |
Founded | 1812 |
Named for | Richard Mentor Johnson |
Seat | Vienna |
Largest city | Vienna |
Area | |
• Total | 349 sq mi (900 km2) |
• Land | 344 sq mi (890 km2) |
• Water | 4.9 sq mi (13 km2) 1.4% |
Population (2020) | |
• Total | 13,308 ![]() |
• Density | 38/sq mi (15/km2) |
Time zone | UTC−6 (Central) |
• Summer (DST) | UTC−5 (CDT) |
Congressional district | 12th |
Johnson County is a county in the U.S. state of Illinois. According to the 2020 census, it has a population of 13,308.[1] Its county seat is Vienna.[2] It is located in the southern portion of Illinois known locally as "Little Egypt".