- Maryland Ponderosa
- Marywood
- McCanns Corner
- McComas
- McGuigan Park
- Meadow Springs
- Meadow Stream
- Meadowbrook
- Meadowlark Estates
- Meadowood
- Meadowvale
- Melrose
- Michaels Corner
- Michaels Meadows
- Michaelsville
- Midsummer Hill
- Mill Green
- Mill Green Acres
- Mill Stone Estates
- Millers Store
- Millwood
- Minefield
- Monks Island
- Monocacy Island
- Montford Glen
- Montreal Acres
- Moores Mill
- Moorland
- Mount Bush Estates
- Mount Vernon Estates