| Harpenden to Decatur (Georgia) | 4,185.90 mi (6,736.55 km) |
| Harpenden to Decatur (Illinois) | 4,074.43 mi (6,557.16 km) |
| Harpenden to Deer Park (New York) | 3,415.37 mi (5,496.51 km) |
| Harpenden to Deer Park (Texas) | 4,825.05 mi (7,765.17 km) |
| Harpenden to Deerfield (Illinois) | 3,924.12 mi (6,315.26 km) |
| Harpenden to Deerfield Beach (Florida) | 4,385.19 mi (7,057.28 km) |
| Harpenden to Defiance (Ohio) | 3,831.59 mi (6,166.35 km) |
| Harpenden to DeForest (Wisconsin) | 3,930.38 mi (6,325.33 km) |
| Harpenden to DeKalb (Illinois) | 3,968.91 mi (6,387.34 km) |
| Harpenden to Del Aire (California) | 5,430.82 mi (8,740.05 km) |
| Harpenden to Del City (Oklahoma) | 4,616.31 mi (7,429.23 km) |
| Harpenden to Del Rio (Texas) | 5,065.64 mi (8,152.35 km) |
| Harpenden to DeLand (Florida) | 4,297.02 mi (6,915.39 km) |
| Harpenden to Delano (California) | 5,352.73 mi (8,614.38 km) |
| Harpenden to Delaware (Ohio) | 3,827.06 mi (6,159.05 km) |
