| Irthlingborough to Montalegre | 799.36 mi (1,286.45 km) |
| Irthlingborough to Montemor-o-Novo | 1,012.66 mi (1,629.72 km) |
| Irthlingborough to Montemor-o-Velho | 922.89 mi (1,485.25 km) |
| Irthlingborough to Montijo | 1,022.74 mi (1,645.94 km) |
| Irthlingborough to Mortagua | 897.07 mi (1,443.69 km) |
| Irthlingborough to Moura | 1,034.23 mi (1,664.43 km) |
| Irthlingborough to Murtosa | 885.65 mi (1,425.32 km) |
| Irthlingborough to Nazare | 966.80 mi (1,555.91 km) |
| Irthlingborough to Nelas | 884.55 mi (1,423.54 km) |
| Irthlingborough to Obidos | 984.12 mi (1,583.79 km) |
| Irthlingborough to Odemira | 1,089.74 mi (1,753.77 km) |
| Irthlingborough to Odivelas | 1,021.10 mi (1,643.31 km) |
| Irthlingborough to Oeiras | 1,030.65 mi (1,658.67 km) |
| Irthlingborough to Olhao | 1,113.67 mi (1,792.28 km) |
| Irthlingborough to Oliveira de Azemeis | 875.67 mi (1,409.26 km) |
