| | Warren County | IA | 19181 | | 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=WarrenCounty+IA |
| | 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 |
| | Wayne County | IA | 19185 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=WayneCounty+IA |
| | Webster County | IA | 19187 | | Fort Dodge, IA 22700 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=WebsterCounty+IA |
| | Winnebago County | IA | 19189 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=WinnebagoCounty+IA |
| | Winneshiek County | IA | 19191 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=WinneshiekCounty+IA |
| | Woodbury County | IA | 19193 | | Sioux City, IA-NE-SD 43580 | Sioux City-Le Mars,
IA-NE-SD 512 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=WoodburyCounty+IA |
| | Worth County | IA | 19195 | | Mason City, IA 32380 | | Outlying | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=WorthCounty+IA |
| | Wright County | IA | 19197 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=WrightCounty+IA |