| Merthyr Tudful to Montijo | 900.29 mi (1,448.88 km) |
| Merthyr Tudful to Montilla | 980.24 mi (1,577.55 km) |
| Merthyr Tudful to Montmelo | 752.29 mi (1,210.69 km) |
| Merthyr Tudful to Montornes del Valles | 753.25 mi (1,212.23 km) |
| Merthyr Tudful to Montoro | 949.65 mi (1,528.31 km) |
| Merthyr Tudful to Monzon | 699.80 mi (1,126.21 km) |
| Merthyr Tudful to Mora | 833.42 mi (1,341.25 km) |
| Merthyr Tudful to Moralzarzal | 765.24 mi (1,231.54 km) |
| Merthyr Tudful to Moron de la Frontera | 1,015.26 mi (1,633.90 km) |
| Merthyr Tudful to Mostoles | 788.68 mi (1,269.25 km) |
| Merthyr Tudful to Motril | 1,035.94 mi (1,667.18 km) |
| Merthyr Tudful to Muchamiel | 931.82 mi (1,499.62 km) |
| Merthyr Tudful to Mula | 951.07 mi (1,530.59 km) |
| Merthyr Tudful to Munguia | 580.10 mi (933.58 km) |
| Merthyr Tudful to Murcia | 956.74 mi (1,539.72 km) |
