| Merthyr Tudful to Dixon (Illinois) | 3,888.26 mi (6,257.55 km) |
| Merthyr Tudful to Dobbs Ferry (New York) | 3,304.80 mi (5,318.56 km) |
| Merthyr Tudful to Doctor Phillips (Florida) | 4,208.44 mi (6,772.84 km) |
| Merthyr Tudful to Dodge City (Kansas) | 4,483.92 mi (7,216.17 km) |
| Merthyr Tudful to Dolton (Illinois) | 3,825.84 mi (6,157.09 km) |
| Merthyr Tudful to Donna (Texas) | 5,009.27 mi (8,061.64 km) |
| Merthyr Tudful to Dorado (Puerto Rico) | 4,070.63 mi (6,551.04 km) |
| Merthyr Tudful to Doral (Florida) | 4,292.44 mi (6,908.02 km) |
| Merthyr Tudful to Doraville (Georgia) | 4,056.40 mi (6,528.14 km) |
| Merthyr Tudful to Dothan (Alabama) | 4,233.77 mi (6,813.59 km) |
| Merthyr Tudful to Douglas (Arizona) | 5,171.08 mi (8,322.04 km) |
| Merthyr Tudful to Douglas (Georgia) | 4,114.53 mi (6,621.70 km) |
| Merthyr Tudful to Douglasville (Georgia) | 4,082.38 mi (6,569.95 km) |
| Merthyr Tudful to Dover (Delaware) | 3,453.01 mi (5,557.08 km) |
| Merthyr Tudful to Dover (New Hampshire) | 3,092.19 mi (4,976.40 km) |
