- Midvale
- Mesquakie Indian Settlement
- Merle Junction
- Monette
- Munterville
- Macey
- Medora
- Mayflower Mobile Home Park
- Meadow Brook Mobile Home Park
- Magill
- Mardan Mobile Home Court
- Midway
- Morningside
- Mount Lucia
- Maple Leaf
- Meltonville
- Malcom
- Mallard
- Maloy
- Manilla
- Manly
- Manson
- Maquoketa
- Marble Rock
- Marion
- Morhain
- Marshalltown
- Martelle
- Martensdale
- Mason City