- Merthyr
- Merthyr Cynog
- Merthyr Mawr
- Merthyr Tydfil
- Merthyr Vale
- Meyllteyrn
- Middle Mill
- Milford Haven
- Minera
- Minffordd
- Minwear
- Mitchel Troy
- Mochdre
- Moel-tryfan
- Moelfre
- Monington
- Monknash
- Monkswood
- Maesygwartha
- Manson
- Merthyr Tewdrig
- Mitcheltroy Common
- Mynydd-bach
- Morfa
- Morfa Bach
- Morfa Nefyn
- Morriston
- Morvil
- Mostyn
- Mountain Ash