| Merthyr Tudful to Mitcham | 140.54 mi (226.18 km) |
| Merthyr Tudful to Mold | 98.86 mi (159.10 km) |
| Merthyr Tudful to Molesey | 131.60 mi (211.80 km) |
| Merthyr Tudful to Monkseaton | 241.30 mi (388.34 km) |
| Merthyr Tudful to Monmouth | 28.51 mi (45.88 km) |
| Merthyr Tudful to Montrose | 345.01 mi (555.24 km) |
| Merthyr Tudful to Morden | 138.70 mi (223.22 km) |
| Merthyr Tudful to Morecambe | 162.37 mi (261.31 km) |
| Merthyr Tudful to Moreton | 115.10 mi (185.24 km) |
| Merthyr Tudful to Morley | 157.25 mi (253.06 km) |
| Merthyr Tudful to Morpeth | 246.56 mi (396.80 km) |
| Merthyr Tudful to Morriston | 24.62 mi (39.62 km) |
| Merthyr Tudful to Mosbrough | 138.29 mi (222.55 km) |
| Merthyr Tudful to Mossley | 134.68 mi (216.74 km) |
| Merthyr Tudful to Moston | 132.30 mi (212.91 km) |
