| Harpenden to Ifield | 48.36 mi (77.83 km) |
| Harpenden to Ilford | 25.98 mi (41.81 km) |
| Harpenden to Ilfracombe | 167.37 mi (269.35 km) |
| Harpenden to Ilkeston | 89.32 mi (143.75 km) |
| Harpenden to Ilkley | 157.98 mi (254.24 km) |
| Harpenden to Immingham | 124.25 mi (199.95 km) |
| Harpenden to Ince-in-Makerfield | 151.72 mi (244.17 km) |
| Harpenden to Inverness | 420.44 mi (676.64 km) |
| Harpenden to Inverurie | 386.02 mi (621.25 km) |
| Harpenden to Ipswich | 66.37 mi (106.82 km) |
| Harpenden to Irlam | 142.03 mi (228.58 km) |
| Harpenden to Irthlingborough | 36.72 mi (59.09 km) |
| Harpenden to Irvine | 316.20 mi (508.88 km) |
| Harpenden to Islington | 21.71 mi (34.95 km) |
| Harpenden to Iver | 21.53 mi (34.65 km) |
