| | Ogle County | IL | 17141 | | Rochelle, IL 40300 | Rockford-Freeport-Rochelle,
IL 466 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=OgleCounty+IL |
| | Peoria County | IL | 17143 | | Peoria, IL 37900 | Peoria-Canton, IL 427 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=PeoriaCounty+IL |
| | Pike County | IL | 17149 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=PikeCounty+IL |
| | Richland County | IL | 17159 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=RichlandCounty+IL |
| | Rock Island County | IL | 17161 | | Davenport-Moline-Rock
Island, IA-IL 19340 | Davenport-Moline, IA-IL 209 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=RockIslandCounty+IL |
| | St. Clair County | IL | 17163 | | St. Louis, MO-IL 41180 | St. Louis-St.
Charles-Farmington, MO-IL 476 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=St.ClairCounty+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 |
| | Washington County | IL | 17189 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=WashingtonCounty+IL |
| | Wayne County | IL | 17191 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=WayneCounty+IL |
| | Will County | IL | 17197 | 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=WillCounty+IL |