| | Aroostook County | ME | 23003 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=AroostookCounty+ME |
| | Franklin County | ME | 23007 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=FranklinCounty+ME |
| | Hancock County | ME | 23009 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=HancockCounty+ME |
| | Kennebec County | ME | 23011 | | Augusta-Waterville, ME 12300 | | Central | nonmetro county (rural) | federal/state
government-dependent | https://maps.google.com/?q=KennebecCounty+ME |
| | Knox County | ME | 23013 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=KnoxCounty+ME |
| | Lincoln County | ME | 23015 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=LincolnCounty+ME |
| | Oxford County | ME | 23017 | | | | | nonmetro county (rural) | recreation | https://maps.google.com/?q=OxfordCounty+ME |
| | Penobscot County | ME | 23019 | | Bangor, ME 12620 | | Central | metro county (urban) | nonspecialized | https://maps.google.com/?q=PenobscotCounty+ME |
| | Piscataquis County | ME | 23021 | | | | | nonmetro county (rural) | manufacturing-dependent | https://maps.google.com/?q=PiscataquisCounty+ME |
| | Somerset County | ME | 23025 | | | | | nonmetro county (rural) | nonspecialized | https://maps.google.com/?q=SomersetCounty+ME |