| Harpenden to Melzo | 622.94 mi (1,002.53 km) |
| Harpenden to Mendicino | 1,175.09 mi (1,891.12 km) |
| Harpenden to Menfi | 1,175.63 mi (1,891.99 km) |
| Harpenden to Mentana | 911.14 mi (1,466.34 km) |
| Harpenden to Merano | 628.26 mi (1,011.09 km) |
| Harpenden to Merate | 613.29 mi (987.00 km) |
| Harpenden to Mercato San Severino | 1,045.76 mi (1,682.98 km) |
| Harpenden to Mercogliano | 1,037.40 mi (1,669.54 km) |
| Harpenden to Mesagne | 1,159.51 mi (1,866.04 km) |
| Harpenden to Messina | 1,215.13 mi (1,955.57 km) |
| Harpenden to Mestre | 720.39 mi (1,159.35 km) |
| Harpenden to Mestrino | 705.41 mi (1,135.25 km) |
| Harpenden to Milan | 617.36 mi (993.54 km) |
| Harpenden to Milazzo | 1,204.19 mi (1,937.95 km) |
| Harpenden to Minerbio | 735.77 mi (1,184.10 km) |
