| | Alexander County | IL | 17003 | | Cape Girardeau, MO-IL 16020 | Cape Girardeau-Sikeston,
MO-IL 164 | Outlying | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=AlexanderCounty+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 |
| | Williamson County | IL | 17199 | | Marion-Herrin, IL 32060 | Carbondale-Marion-Herrin,
IL 166 | Central | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=WilliamsonCounty+IL |
| | Champaign County | IL | 17019 | | Champaign-Urbana, IL 16580 | Champaign-Urbana-Denville,
IL 169 | Central | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=ChampaignCounty+IL |
| | Ford County | IL | 17053 | | Champaign-Urbana, IL 16580 | Champaign-Urbana-Denville,
IL 169 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=FordCounty+IL |
| | Piatt County | IL | 17147 | | Champaign-Urbana, IL 16580 | Champaign-Urbana-Denville,
IL 169 | Outlying | metro county (urban) | farm-dependent | https://maps.google.com/?q=PiattCounty+IL |
| | Vermilion County | IL | 17183 | | Danville, IL 19180 | Champaign-Urbana-Denville,
IL 169 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=VermilionCounty+IL |
| | Bureau County | IL | 17011 | | Ottawa, IL 36837 | Chicago-Naperville,
IL-IN-WI 176 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=BureauCounty+Illinois |
| | Cook County | IL | 17031 | Chicago-Naperville-Schaumburg,
IL 16984 | Chicago-Naperville-Elgin,
IL-IN 16980 | Chicago-Naperville,
IL-IN-WI 176 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=CookCounty+IL |
| | DeKalb County | IL | 17037 | Elgin, IL 20994 | Chicago-Naperville-Elgin,
IL-IN 16980 | Chicago-Naperville,
IL-IN-WI 176 | Outlying | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=DeKalbCounty+IL |