- Millcreek
- Miller Creek Park Mobile Home Park
- Millpond Acres
- Millsboro
- Millside
- Milltown
- Millville
- Milton
- Minners Corners
- Minquadale
- Minquadale Trailer Village
- Mispillion Light
- Mission
- Misty Pines
- Mitchell Estates
- Mockingbird Hill
- Mockingbird Hills
- Monroe Park
- Montchan
- Montchanin
- Montclare
- Monterey Farms
- Montgomery Woods
- Moores Acres
- Moores Corner
- Moores Lake Development
- Morgan Island
- Morris Estates
- Morris Mill
- Mount Cuba