| Harpenden to March | 54.00 mi (86.91 km) |
| Harpenden to Margate | 80.28 mi (129.19 km) |
| Harpenden to Market Drayton | 117.19 mi (188.60 km) |
| Harpenden to Market Harborough | 51.57 mi (83.00 km) |
| Harpenden to Marlow | 25.06 mi (40.32 km) |
| Harpenden to Marple | 130.57 mi (210.12 km) |
| Harpenden to Marton | 191.19 mi (307.70 km) |
| Harpenden to Maryport | 238.40 mi (383.66 km) |
| Harpenden to Matlock | 104.35 mi (167.93 km) |
| Harpenden to Melksham | 82.62 mi (132.96 km) |
| Harpenden to Meltham | 137.70 mi (221.61 km) |
| Harpenden to Melton Mowbray | 69.31 mi (111.55 km) |
| Harpenden to Merthyr Tudful | 129.43 mi (208.29 km) |
| Harpenden to Methil | 320.55 mi (515.88 km) |
| Harpenden to Mexborough | 122.56 mi (197.24 km) |
