| | | Bell County | KY | 21013 | | Middlesborough, KY 33180 | Middlesborough-Corbin, KY 371 | Central | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=BellCounty+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 |
| | | Carlisle County | KY | 21039 | | Paducah, KY-IL 37140 | Paducah-Mayfield, KY-IL 424 | Outlying | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=CarlisleCounty+KY |
| | | Carroll County | KY | 21041 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=CarrollCounty+KY |
| | | Carter County | KY | 21043 | | Huntington-Ashland,
WV-KY-OH 26580 | Charleston-Huntington-Ashland,
WV-OH-KY 170 | Outlying | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=CarterCounty+KY |
| | | Casey County | KY | 21045 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=CaseyCounty+KY |
