| Merthyr Tudful to Dardenne Prairie (Missouri) | 4,081.93 mi (6,569.24 km) |
| Merthyr Tudful to Darien (Illinois) | 3,835.34 mi (6,172.39 km) |
| Merthyr Tudful to Davenport (Iowa) | 3,944.59 mi (6,348.20 km) |
| Merthyr Tudful to Davidson (North Carolina) | 3,839.52 mi (6,179.11 km) |
| Merthyr Tudful to Davie (Florida) | 4,276.19 mi (6,881.86 km) |
| Merthyr Tudful to Davis (California) | 5,179.54 mi (8,335.66 km) |
| Merthyr Tudful to Dayton (Nevada) | 5,072.86 mi (8,163.98 km) |
| Merthyr Tudful to Dayton (Ohio) | 3,777.10 mi (6,078.66 km) |
| Merthyr Tudful to Daytona Beach (Florida) | 4,154.55 mi (6,686.11 km) |
| Merthyr Tudful to De Pere (Wisconsin) | 3,717.52 mi (5,982.77 km) |
| Merthyr Tudful to De Witt (New York) | 3,309.69 mi (5,326.43 km) |
| Merthyr Tudful to Dearborn (Michigan) | 3,624.14 mi (5,832.49 km) |
| Merthyr Tudful to Dearborn Heights (Michigan) | 3,626.49 mi (5,836.27 km) |
| Merthyr Tudful to DeBary (Florida) | 4,179.82 mi (6,726.77 km) |
| Merthyr Tudful to Decatur (Alabama) | 4,135.02 mi (6,654.67 km) |
