- Madison Center (Population: 2,222)
- Madison (Population: 17,858)
- Manchester (Population: 54,740)
- Mansfield (Population: 20,720)
- Marlborough (Population: 5,709)
- Meriden (Population: 58,244)
- Middlebury (Population: 6,451)
- Middlefield (Population: 4,203)
- Middletown (Population: 43,167)
- Milford (Population: 52,305)
- Monroe (Population: 19,247)
- Montville (Population: 18,546)
- Moodus (Population: 1,263)
- Moosup (Population: 3,237)
- Morris (Population: 2,301)
- Mystic (Population: 4,001)
