| | | Washington County | IA | 19183 | | Iowa City, IA 26980 | Cedar Rapids-Iowa City,
IA 168 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=WashingtonCounty+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 |
| | | Marshall County | IA | 19127 | | Marshalltown, IA 32260 | | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=MarshallCounty+IA |
| | | Cerro Gordo County | IA | 19033 | | Mason City, IA 32380 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=CerroGordoCounty+IA |
| | | Worth County | IA | 19195 | | Mason City, IA 32380 | | Outlying | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=WorthCounty+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 |
| | | Harrison County | IA | 19085 | | Omaha, NE-IA 36540 | Omaha-Fremont, NE-IA 420 | Outlying | metro county (urban) | farm-dependent | https://maps.google.com/?q=HarrisonCounty+IA |
| | | Mills County | IA | 19129 | | Omaha, NE-IA 36540 | Omaha-Fremont, NE-IA 420 | Outlying | metro county (urban) | federal/state
government-dependent | https://maps.google.com/?q=MillsCounty+IA |
| | | Pottawattamie County | IA | 19155 | | Omaha, NE-IA 36540 | Omaha-Fremont, NE-IA 420 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=PottawattamieCounty+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 |
