| Merthyr Tudful to Madison (New Jersey) | 3,338.12 mi (5,372.18 km) |
| Merthyr Tudful to Madison (Wisconsin) | 3,828.05 mi (6,160.65 km) |
| Merthyr Tudful to Madison Heights (Michigan) | 3,611.25 mi (5,811.75 km) |
| Merthyr Tudful to Madison Heights (Virginia) | 3,677.59 mi (5,918.51 km) |
| Merthyr Tudful to Madisonville (Kentucky) | 4,022.52 mi (6,473.62 km) |
| Merthyr Tudful to Magalia (California) | 5,103.42 mi (8,213.17 km) |
| Merthyr Tudful to Magna (Utah) | 4,753.23 mi (7,649.58 km) |
| Merthyr Tudful to Magnolia (Arkansas) | 4,448.98 mi (7,159.93 km) |
| Merthyr Tudful to Maili (Hawaii) | 7,156.94 mi (11,517.98 km) |
| Merthyr Tudful to Maitland (Florida) | 4,194.35 mi (6,750.15 km) |
| Merthyr Tudful to Makakilo (Hawaii) | 7,158.99 mi (11,521.28 km) |
| Merthyr Tudful to Malden (Massachusetts) | 3,130.07 mi (5,037.36 km) |
| Merthyr Tudful to Malibu (California) | 5,342.79 mi (8,598.39 km) |
| Merthyr Tudful to Maltby (Washington) | 4,667.40 mi (7,511.46 km) |
| Merthyr Tudful to Malvern (Arkansas) | 4,378.09 mi (7,045.85 km) |
