| | Yellowstone County | MT | 30111 | | Billings, MT 13740 | | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=YellowstoneCounty+MT |
| | Wibaux County | MT | 30109 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=WibauxCounty+MT |
| | Wheatland County | MT | 30107 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=WheatlandCounty+MT |
| | Valley County | MT | 30105 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=ValleyCounty+MT |
| | Treasure County | MT | 30103 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=TreasureCounty+MT |
| | Toole County | MT | 30101 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=TooleCounty+MT |
| | Teton County | MT | 30099 | | | | | nonmetro county (rural) | farm-dependent | https://maps.google.com/?q=TetonCounty+MT |
| | Sweet Grass County | MT | 30097 | | | | | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=SweetGrassCounty+MT |
| | Stillwater County | MT | 30095 | | Billings, MT 13740 | | Outlying | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=StillwaterCounty+MT |
| | Silver Bow County | MT | 30093 | | Butte-Silver Bow, MT 15580 | | Central | nonmetro county (rural) | mining-dependent | https://maps.google.com/?q=SilverBowCounty+MT |