| | | Jersey County | IL | 17083 | | St. Louis, MO-IL 41180 | St. Louis-St.
Charles-Farmington, MO-IL 476 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=JerseyCounty+IL |
| | | Jefferson County | IL | 17081 | | Mount Vernon, IL 34500 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=JeffersonCounty+IL |
| | | Jasper County | IL | 17079 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=JasperCounty+IL |
| | | Jackson County | IL | 17077 | | Carbondale, IL 16060 | Carbondale-Marion-Herrin,
IL 166 | Central | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=JacksonCounty+IL |
| | | Iroquois County | IL | 17075 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=IroquoisCounty+IL |
| | | Henry County | IL | 17073 | | Davenport-Moline-Rock
Island, IA-IL 19340 | Davenport-Moline, IA-IL 209 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=HenryCounty+IL |
| | | Henderson County | IL | 17071 | | Burlington, IA-IL 15460 | Burlington-Fort Madison,
IA-IL 161 | Outlying | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=HendersonCounty+IL |
| | | Hardin County | IL | 17069 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=HardinCounty+IL |
| | | Hancock County | IL | 17067 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=HancockCounty+IL |
| | | Hamilton County | IL | 17065 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=HamiltonCounty+IL |
