| | | Champaign County | OH | 39021 | | Urbana, OH 46500 | Dayton-Springfield-Kettering,
OH 212 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=ChampaignCounty+OH |
| | | Clark County | OH | 39023 | | Springfield, OH 44220 | Dayton-Springfield-Kettering,
OH 212 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=ClarkCounty+OH |
| | | Clermont County | OH | 39025 | | Cincinnati, OH-KY-IN 17140 | Cincinnati-Wilmington,
OH-KY-IN 178 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=ClermontCounty+OH |
| | | Clinton County | OH | 39027 | | Wilmington, OH 48940 | Cincinnati-Wilmington,
OH-KY-IN 178 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=ClintonCounty+OH |
| | | Columbiana County | OH | 39029 | | Salem, OH 41400 | Youngstown-Warren-Salem,
OH 566 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=ColumbianaCounty+OH |
| | | Coshocton County | OH | 39031 | | Coshocton, OH 18740 | Cleveland-Akron-Canton,
OH 184 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=CoshoctonCounty+OH |
| | | Crawford County | OH | 39033 | | Bucyrus, OH 15340 | Mansfield-Ashland-Bucyrus,
OH 360 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=CrawfordCounty+OH |
| | | Cuyahoga County | OH | 39035 | | Cleveland, OH 17410 | Cleveland-Akron-Canton,
OH 184 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=CuyahogaCounty+OH |
| | | Darke County | OH | 39037 | | Greenville, OH 24820 | Dayton-Springfield-Kettering,
OH 212 | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=DarkeCounty+OH |
| | | Defiance County | OH | 39039 | | Defiance, OH 19580 | | Central | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=DefianceCounty+OH |
