| Merthyr Tudful to Merrick (New York) | 3,307.21 mi (5,322.44 km) |
| Merthyr Tudful to Merrifield (Virginia) | 3,536.66 mi (5,691.70 km) |
| Merthyr Tudful to Merrillville (Indiana) | 3,822.19 mi (6,151.22 km) |
| Merthyr Tudful to Merritt Island (Florida) | 4,180.48 mi (6,727.84 km) |
| Merthyr Tudful to Mesa (Arizona) | 5,137.63 mi (8,268.22 km) |
| Merthyr Tudful to Mesquite (Nevada) | 5,034.08 mi (8,101.57 km) |
| Merthyr Tudful to Mesquite (Texas) | 4,607.56 mi (7,415.15 km) |
| Merthyr Tudful to Metairie (Louisiana) | 4,491.46 mi (7,228.31 km) |
| Merthyr Tudful to Methuen Town (Massachusetts) | 3,123.07 mi (5,026.10 km) |
| Merthyr Tudful to Metuchen (New Jersey) | 3,345.18 mi (5,383.55 km) |
| Merthyr Tudful to Mexico (Missouri) | 4,106.53 mi (6,608.83 km) |
| Merthyr Tudful to Miami (Florida) | 4,287.80 mi (6,900.55 km) |
| Merthyr Tudful to Miami (Oklahoma) | 4,333.10 mi (6,973.45 km) |
| Merthyr Tudful to Miami Beach (Florida) | 4,283.14 mi (6,893.04 km) |
| Merthyr Tudful to Miami Gardens (Florida) | 4,281.14 mi (6,889.83 km) |
