- Martinsville
- Martinton
- Mary Meadows
- Marydale
- Maryland
- Maryland Place
- Maryland Subdivision
- Maryville
- Marywood
- Mascoutah
- Mason
- Mason
- Mason City
- Massac City
- Massbach
- Matanzas
- Matanzas Beach
- Matanzas Island
- Matherville
- Matteson
- Matthews
- Matthews Junction
- Mattoon
- Maud
- Maunie
- Maxey Island
- Maxwell
- Mayberry
- Mayfair
- Mayo Island