| | Adair County | KY | 21001 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=AdairCounty+KY |
| | Boyle County | KY | 21021 | | Danville, KY 19220 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=BoyleCounty+KY |
| | Breathitt County | KY | 21025 | | | | | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=BreathittCounty+KY |
| | Breckinridge County | KY | 21027 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=BreckinridgeCounty+KY |
| | Caldwell County | KY | 21033 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=CaldwellCounty+KY |
| | Calloway County | KY | 21035 | | Murray, KY 34660 | | Central | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=CallowayCounty+KY |
| | Carroll County | KY | 21041 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=CarrollCounty+KY |
| | Casey County | KY | 21045 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=CaseyCounty+KY |
| | Christian County | KY | 21047 | | Clarksville, TN-KY 17300 | | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=ChristianCounty+KY |
| | Clinton County | KY | 21053 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=ClintonCounty+KY |