| Merthyr Tudful to Morristown (New Jersey) | 3,338.96 mi (5,373.53 km) |
| Merthyr Tudful to Morristown (Tennessee) | 3,907.06 mi (6,287.80 km) |
| Merthyr Tudful to Morrisville (North Carolina) | 3,740.79 mi (6,020.21 km) |
| Merthyr Tudful to Morro Bay (California) | 5,333.76 mi (8,583.86 km) |
| Merthyr Tudful to Morton (Illinois) | 3,945.03 mi (6,348.92 km) |
| Merthyr Tudful to Morton Grove (Illinois) | 3,814.28 mi (6,138.50 km) |
| Merthyr Tudful to Moscow (Idaho) | 4,581.89 mi (7,373.84 km) |
| Merthyr Tudful to Moses Lake (Washington) | 4,626.01 mi (7,444.85 km) |
| Merthyr Tudful to Moss Bluff (Louisiana) | 4,598.65 mi (7,400.81 km) |
| Merthyr Tudful to Moss Point (Mississippi) | 4,402.54 mi (7,085.21 km) |
| Merthyr Tudful to Moultrie (Georgia) | 4,169.66 mi (6,710.42 km) |
| Merthyr Tudful to Mounds View (Minnesota) | 3,876.89 mi (6,239.26 km) |
| Merthyr Tudful to Mount Airy (North Carolina) | 3,783.01 mi (6,088.16 km) |
| Merthyr Tudful to Mount Clemens (Michigan) | 3,598.59 mi (5,791.37 km) |
| Merthyr Tudful to Mount Dora (Florida) | 4,196.22 mi (6,753.17 km) |
