| | Marshall County | KY | 21157 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=MarshallCounty+KY |
| | Martin County | KY | 21159 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=MartinCounty+KY |
| | Mason County | KY | 21161 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MasonCounty+Kentucky |
| | Mercer County | KY | 21167 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=MercerCounty+KY |
| | Monroe County | KY | 21171 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=MonroeCounty+KY |
| | Morgan County | KY | 21175 | | | | | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=MorganCounty+KY |
| | Muhlenberg County | KY | 21177 | | | | | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=MuhlenbergCounty+Kentucky |
| | Nicholas County | KY | 21181 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=NicholasCounty+KY |
| | Ohio County | KY | 21183 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=OhioCounty+KY |
| | Owen County | KY | 21187 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=OwenCounty+KY |