| Merthyr Tudful to Desert Hot Springs (California) | 5,273.00 mi (8,486.07 km) |
| Merthyr Tudful to DeSoto (Texas) | 4,626.62 mi (7,445.82 km) |
| Merthyr Tudful to Destin (Florida) | 4,319.28 mi (6,951.21 km) |
| Merthyr Tudful to Destrehan (Louisiana) | 4,500.97 mi (7,243.61 km) |
| Merthyr Tudful to Detroit (Michigan) | 3,616.67 mi (5,820.48 km) |
| Merthyr Tudful to Diamond Bar (California) | 5,313.00 mi (8,550.44 km) |
| Merthyr Tudful to Diamond Springs (California) | 5,144.26 mi (8,278.89 km) |
| Merthyr Tudful to Dickinson (North Dakota) | 4,127.01 mi (6,641.78 km) |
| Merthyr Tudful to Dickinson (Texas) | 4,716.64 mi (7,590.70 km) |
| Merthyr Tudful to Dickson (Tennessee) | 4,078.16 mi (6,563.17 km) |
| Merthyr Tudful to Difficult Run (Virginia) | 3,539.68 mi (5,696.56 km) |
| Merthyr Tudful to Dinuba (California) | 5,220.76 mi (8,402.00 km) |
| Merthyr Tudful to Discovery Bay (California) | 5,212.34 mi (8,388.46 km) |
| Merthyr Tudful to Dix Hills (New York) | 3,291.84 mi (5,297.70 km) |
| Merthyr Tudful to Dixon (California) | 5,188.40 mi (8,349.93 km) |
