- Megquier Island
- Melvin Heights
- Mercer
- Merchant Island
- Merepoint
- Merrill Corner
- Merrill Island
- Merrill Isle
- Merritt Island
- Merrow Island
- Merrow Landing
- Merry Island
- Merrymeeting Trailer Park
- Metallak Island
- Metinic Green Island
- Metinic Island
- Mexico
- Michaud Island
- Michigan Settlement
- Middle Black Rock
- Middle Dam
- Middle Intervale
- Middle Island
- Middle Island
- Middle Island
- Middle Island
- Middle Mark Island
- Midway Island
- Milbridge
- Mile Island