| | Benton County | IA | 19011 | | Cedar Rapids, IA 16300 | Cedar Rapids-Iowa City,
IA 168 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=BentonCounty+IA |
| | Boone County | IA | 19015 | | Ames, IA 11180 | Des Moines-West Des
Moines-Ames, IA 218 | Outlying | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=BooneCounty+Iowa |
| | Bremer County | IA | 19017 | | Waterloo-Cedar Falls, IA 47940 | | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=BremerCounty+IA |
| | Grundy County | IA | 19075 | | Waterloo-Cedar Falls, IA 47940 | | Outlying | metro county (urban) | farm-dependent | https://maps.google.com/?q=GrundyCounty+IA |
| | Guthrie County | IA | 19077 | | Des Moines-West Des
Moines, IA 19780 | Des Moines-West Des
Moines-Ames, IA 218 | Outlying | metro county (urban) | farm-dependent | https://maps.google.com/?q=GuthrieCounty+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 |
| | Jasper County | IA | 19099 | | Des Moines-West Des
Moines, IA 19780 | Des Moines-West Des
Moines-Ames, IA 218 | Outlying | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=JasperCounty+Iowa |
| | Jones County | IA | 19105 | | Cedar Rapids, IA 16300 | Cedar Rapids-Iowa City,
IA 168 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=JonesCounty+IA |
| | Madison County | IA | 19121 | | Des Moines-West Des
Moines, IA 19780 | Des Moines-West Des
Moines-Ames, IA 218 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=MadisonCounty+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 |