| Merthyr Tudful to Mendota Heights (Minnesota) | 3,884.82 mi (6,252.02 km) |
| Merthyr Tudful to Menifee (California) | 5,309.33 mi (8,544.53 km) |
| Merthyr Tudful to Menlo Park (California) | 5,254.82 mi (8,456.82 km) |
| Merthyr Tudful to Menomonee Falls (Wisconsin) | 3,776.78 mi (6,078.13 km) |
| Merthyr Tudful to Menomonie (Wisconsin) | 3,839.38 mi (6,178.89 km) |
| Merthyr Tudful to Mentor (Ohio) | 3,577.45 mi (5,757.35 km) |
| Merthyr Tudful to Mequon (Wisconsin) | 3,767.58 mi (6,063.33 km) |
| Merthyr Tudful to Merced (California) | 5,211.76 mi (8,387.52 km) |
| Merthyr Tudful to Mercedes (Texas) | 5,003.18 mi (8,051.85 km) |
| Merthyr Tudful to Mercer Island (Washington) | 4,684.12 mi (7,538.37 km) |
| Merthyr Tudful to Mercerville (New Jersey) | 3,371.92 mi (5,426.58 km) |
| Merthyr Tudful to Meriden (Connecticut) | 3,238.48 mi (5,211.83 km) |
| Merthyr Tudful to Meridian (Idaho) | 4,733.66 mi (7,618.09 km) |
| Merthyr Tudful to Meridian (Mississippi) | 4,311.34 mi (6,938.43 km) |
| Merthyr Tudful to Merriam (Kansas) | 4,221.41 mi (6,793.71 km) |
