| | Montrose County | CO | 08085 | | Montrose, CO 33940 | | Central | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MontroseCounty+CO |
| | Montezuma County | CO | 08083 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=MontezumaCounty+CO |
| | Moffat County | CO | 08081 | | Steamboat Springs, CO 44460 | | Outlying | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=MoffatCounty+Colorado |
| | Mineral County | CO | 08079 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=MineralCounty+CO |
| | Mesa County | CO | 08077 | | Grand Junction, CO 24300 | | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=MesaCounty+CO |
| | Logan County | CO | 08075 | | Sterling, CO 44540 | | Central | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=LoganCounty+CO |
| | Lincoln County | CO | 08073 | | | | | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=LincolnCounty+CO |
| | Las Animas County | CO | 08071 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=LasAnimasCounty+CO |
| | Larimer County | CO | 08069 | | Fort Collins-Loveland, CO 22660 | | Central | metro county (urban) | recreation | https://maps.google.com/?q=LarimerCounty+CO |
| | Lake County | CO | 08065 | | Breckenridge, CO 14720 | | Outlying | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=LakeCounty+CO |