| County | FIPS |
|---|---|
| Androscoggin County | 23001 |
| Aroostook County | 23003 |
| Cumberland County | 23005 |
| Franklin County | 23007 |
| Hancock County | 23009 |
| Kennebec County | 23011 |
| Knox County | 23013 |
| Lincoln County | 23015 |
| Oxford County | 23017 |
| Penobscot County | 23019 |
| Piscataquis County | 23021 |
| Sagadahoc County | 23023 |
| Somerset County | 23025 |
| Waldo County | 23027 |
| Washington County | 23029 |
| York County | 23031 |