- Monte Cristo
- Montesano
- Monument Island
- Moody
- Moon Island
- Moona
- Moore
- Moores Corner
- Moores Mobile Manor
- Moorland
- Moorlands
- Mora
- Morganville
- Morningside
- Morton
- Moses
- Moses Lake
- Moses Lake North
- Mossyrock
- Moulton
- Mount Hope
- Mount Pleasant
- Mount Pleasant
- Mount Si Mobile Home Park
- Mount Vernon
- Mount View
- Mount View Villa Mobile Home Park
- Mount Vista
- Mountain Brook
- Mountain Home Park