Johnson County, Illinois Basics:
Johnson County Illinois - Government Site
Population: 12,786
Area: 344 square miles
County seat: Vienna
Area code(s) in use: 618
Time zone: CST
High school graduate or higher: 81.7%
Bachelor's degree or higher: 14.9%
Median household income: $42,027
Persons in poverty: 11.3%
Home ownership rate: 82.9%
Mean travel time to work: 26.2 minutes
Adjacent counties:
Massac Pope Pulaski Saline Union Williamson