| | | Trigg County | KY | 21221 | | Clarksville, TN-KY 17300 | | Outlying | metro county (urban) | recreation | https://maps.google.com/?q=TriggCounty+KY |
| | | Boone County | KY | 21015 | | Cincinnati, OH-KY-IN 17140 | Cincinnati-Wilmington,
OH-KY-IN 178 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=BooneCounty+KY |
| | | Boyd County | KY | 21019 | | Huntington-Ashland,
WV-KY-OH 26580 | Charleston-Huntington-Ashland,
WV-OH-KY 170 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=BoydCounty+KY |
| | | Boyle County | KY | 21021 | | Danville, KY 19220 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=BoyleCounty+KY |
| | | Bullitt County | KY | 21029 | | Louisville/Jefferson
County, KY-IN 31140 | Louisville/Jefferson
County--Elizabethtown,
KY-IN 350 | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=BullittCounty+KY |
| | | Caldwell County | KY | 21033 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=CaldwellCounty+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 |
| | | Christian County | KY | 21047 | | Clarksville, TN-KY 17300 | | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=ChristianCounty+KY |
| | | Clark County | KY | 21049 | | Lexington-Fayette, KY 30460 | Lexington-Fayette--Richmond--Frankfort,
KY 336 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=ClarkCounty+KY |
| | | Cumberland County | KY | 21057 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=CumberlandCounty+KY |
