| | | 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 |
| | | 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 |
| | | 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 |
| | | Macoupin County | IL | 17117 | | St. Louis, MO-IL 41180 | St. Louis-St.
Charles-Farmington, MO-IL 476 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=MacoupinCounty+IL |
| | | Marshall County | IL | 17123 | | Peoria, IL 37900 | Peoria-Canton, IL 427 | Outlying | metro county (urban) | manufacturing-dependent | https://maps.google.com/?q=MarshallCounty+IL |
| | | Massac County | IL | 17127 | | Paducah, KY-IL 37140 | Paducah-Mayfield, KY-IL 424 | Outlying | nonmetro county (rural) | recreation | https://maps.google.com/?q=MassacCounty+IL |
| | | Menard County | IL | 17129 | | Springfield, IL 44100 | Springfield-Jacksonville-Lincoln,
IL 522 | Outlying | metro county (urban) | farm-dependent | https://maps.google.com/?q=MenardCounty+IL |
| | | Mercer County | IL | 17131 | | Davenport-Moline-Rock
Island, IA-IL 19340 | Davenport-Moline, IA-IL 209 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=MercerCounty+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 |
| | | Putnam County | IL | 17155 | | Ottawa, IL 36837 | Chicago-Naperville,
IL-IN-WI 176 | Outlying | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=PutnamCounty+Illinois |
