| | Johnson County | KY | 21115 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=JohnsonCounty+KY |
| | Knott County | KY | 21119 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=KnottCounty+KY |
| | Knox County | KY | 21121 | | Corbin, KY 18340 | Middlesborough-Corbin, KY 371 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=KnoxCounty+Kentucky |
| | Laurel County | KY | 21125 | | Corbin, KY 18340 | Middlesborough-Corbin, KY 371 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LaurelCounty+Kentucky |
| | Lawrence County | KY | 21127 | | Huntington-Ashland,
WV-KY-OH 26580 | Charleston-Huntington-Ashland,
WV-OH-KY 170 | Outlying | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LawrenceCounty+KY |
| | Lee County | KY | 21129 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LeeCounty+KY |
| | Leslie County | KY | 21131 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=LeslieCounty+KY |
| | Letcher County | KY | 21133 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=LetcherCounty+KY |
| | Lewis County | KY | 21135 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=LewisCounty+KY |
| | Lincoln County | KY | 21137 | | Danville, KY 19220 | | Outlying | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LincolnCounty+KY |