- Mason Island
- Massapeag
- Miami Shores
- Middle Rock
- Midway
- Milestone Corner
- Millstone
- Mink Island
- Minnie Island
- Mohegan
- Morningside Park
- Mouse Island
- Mystic Seaport
- Mansfield Four Corners
- Mansfield Hollow
- Mashapaug
- Merrow
- Mount Hope
- Mansfield Depot
- Marion
- Marlborough
- Melrose
- Middle Haddam
- Middlebury
- Middlefield
- Milldale
- Millington
- Monroe
- Morris
- Madison