| Harpenden to Montalegre | 774.01 mi (1,245.65 km) |
| Harpenden to Montemor-o-Novo | 985.60 mi (1,586.16 km) |
| Harpenden to Montemor-o-Velho | 897.48 mi (1,444.35 km) |
| Harpenden to Montijo | 996.57 mi (1,603.83 km) |
| Harpenden to Mortagua | 871.21 mi (1,402.08 km) |
| Harpenden to Moura | 1,005.94 mi (1,618.91 km) |
| Harpenden to Murtosa | 860.63 mi (1,385.04 km) |
| Harpenden to Nazare | 941.49 mi (1,515.18 km) |
| Harpenden to Nelas | 858.20 mi (1,381.14 km) |
| Harpenden to Obidos | 958.76 mi (1,542.97 km) |
| Harpenden to Odemira | 1,062.61 mi (1,710.10 km) |
| Harpenden to Odivelas | 995.37 mi (1,601.90 km) |
| Harpenden to Oeiras | 1,005.03 mi (1,617.44 km) |
| Harpenden to Olhao | 1,085.35 mi (1,746.70 km) |
| Harpenden to Oliveira de Azemeis | 850.50 mi (1,368.75 km) |
