| | | Dubuque County | IA | 19061 | | Dubuque, IA 20220 | | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=DubuqueCounty+IA |
| | | Johnson County | IA | 19103 | | Iowa City, IA 26980 | Cedar Rapids-Iowa City,
IA 168 | Central | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=JohnsonCounty+IA |
| | | Lee County | IA | 19111 | | Fort Madison, IA 22800 | Burlington-Fort Madison,
IA-IL 161 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=LeeCounty+IA |
| | | Linn County | IA | 19113 | | Cedar Rapids, IA 16300 | Cedar Rapids-Iowa City,
IA 168 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=LinnCounty+IA |
| | | Mahaska County | IA | 19123 | | Oskaloosa, IA 36820 | Des Moines-West Des
Moines-Ames, IA 218 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MahaskaCounty+IA |
| | | Marion County | IA | 19125 | | Pella, IA 37800 | Des Moines-West Des
Moines-Ames, IA 218 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=MarionCounty+IA |
| | | Marshall County | IA | 19127 | | Marshalltown, IA 32260 | | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=MarshallCounty+IA |
| | | Muscatine County | IA | 19139 | | Muscatine, IA 34700 | Davenport-Moline, IA-IL 209 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=MuscatineCounty+IA |
| | | Plymouth County | IA | 19149 | | Le Mars, IA 30180 | Sioux City-Le Mars,
IA-NE-SD 512 | Central | metro county (urban) | manufacturing-dependent | https://maps.google.com/?q=PlymouthCounty+IA |
| | | Polk County | IA | 19153 | | Des Moines-West Des
Moines, IA 19780 | Des Moines-West Des
Moines-Ames, IA 218 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=PolkCounty+IA |
