| Transit agency | City | Vehicles operated directly | Website |
|---|---|---|---|
| Greater Portland Transit District | Portland | 30 | Official site |
| City of Bangor | Bangor | 20 | Official site |
| Biddeford-Saco-Old Orchard Beach Transit Committee Shuttle Bus | Saco | 12 | Official site |
| Houlton Band of Maliseet Indians | Littleton | 11 | Official site |
| Maine Department of Transportation | Augusta | 7 | Official site |
| Casco Bay Island Transit District | Portland | 4 | Official site |
| City of South Portland | South Portland | 3 | Official site |
| Aroostook Band of Micmacs | Presque Isle | 2 | Official site |
| Lewiston-Auburn Transit Committee | Auburn | 0 | Official site |
| Northern New England Passenger Rail Authority | Portland | 0 | Official site |
| Town of Cranberry Isles | Islesford | 0 | Official site |
Largest first by vehicles operated directly, as each employer reports it to its federal registry.
Source: Federal Transit Administration, National Transit Database 2024 — Reporter Agency Information. Data captured September 30, 2026.