- Marionville
- Marquand
- Manchester School
- Marlborough
- Martin City
- Maywood
- Melville
- Mount Washington
- Marston
- Marthasville
- Maryland Heights
- Mayview
- McBaine
- McCord Bend
- Mary Ridge
- Meacham Park
- Melrose
- Minke
- Monarch
- Morschels
- Mountain Ridge
- McFall
- Mehlville
- Middle Fabius
- Merriam Woods
- Merwin
- Mill Spring
- Millard
- McMullin
- Morley