| | Macon County | MO | 29121 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=MaconCounty+MO |
| | Madison County | MO | 29123 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MadisonCounty+MO |
| | Maries County | MO | 29125 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=MariesCounty+MO |
| | Marion County | MO | 29127 | | Hannibal, MO 25300 | Quincy-Hannibal, IL-MO 448 | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MarionCounty+MO |
| | Mercer County | MO | 29129 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=MercerCounty+MO |
| | Miller County | MO | 29131 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MillerCounty+MO |
| | Mississippi County | MO | 29133 | | Sikeston, MO 43460 | Cape Girardeau-Sikeston,
MO-IL 164 | Outlying | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=MississippiCounty+MO |
| | Moniteau County | MO | 29135 | | Jefferson City, MO 27620 | Columbia-Jefferson
City-Moberly, MO 190 | Outlying | metro county (urban) | nonspecialized | https://maps.google.com/?q=MoniteauCounty+MO |
| | Monroe County | MO | 29137 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=MonroeCounty+MO |
| | Montgomery County | MO | 29139 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MontgomeryCounty+MO |