| Harpenden to Denizli | 1,720.86 mi (2,769.46 km) |
| Harpenden to Derecik | 2,379.59 mi (3,829.58 km) |
| Harpenden to Dereli | 1,975.46 mi (3,179.20 km) |
| Harpenden to Derik | 2,196.63 mi (3,535.14 km) |
| Harpenden to Derinkuyu | 1,921.22 mi (3,091.91 km) |
| Harpenden to Develi | 1,951.88 mi (3,141.25 km) |
| Harpenden to Dicle | 2,143.95 mi (3,450.36 km) |
| Harpenden to Digor | 2,201.66 mi (3,543.22 km) |
| Harpenden to Dikili | 1,572.63 mi (2,530.90 km) |
| Harpenden to Divrigi | 2,018.93 mi (3,249.15 km) |
| Harpenden to Diyadin | 2,247.22 mi (3,616.56 km) |
| Harpenden to Diyarbakir | 2,171.29 mi (3,494.36 km) |
| Harpenden to Doganhisar | 1,806.72 mi (2,907.63 km) |
| Harpenden to Dogansehir | 2,064.15 mi (3,321.93 km) |
| Harpenden to Dogubayazit | 2,264.22 mi (3,643.91 km) |
