| Irthlingborough to Mangualde | 877.26 mi (1,411.81 km) |
| Irthlingborough to Marco de Canavezes | 847.30 mi (1,363.59 km) |
| Irthlingborough to Marinha Grande | 954.54 mi (1,536.18 km) |
| Irthlingborough to Massama | 1,025.10 mi (1,649.74 km) |
| Irthlingborough to Matosinhos | 858.41 mi (1,381.48 km) |
| Irthlingborough to Mealhada | 904.44 mi (1,455.56 km) |
| Irthlingborough to Melgaco | 790.39 mi (1,272.00 km) |
| Irthlingborough to Melres | 859.70 mi (1,383.56 km) |
| Irthlingborough to Mira | 906.81 mi (1,459.37 km) |
| Irthlingborough to Miranda do Corvo | 920.46 mi (1,481.33 km) |
| Irthlingborough to Mirandela | 809.70 mi (1,303.09 km) |
| Irthlingborough to Mogadouro | 811.62 mi (1,306.17 km) |
| Irthlingborough to Moimenta da Beira | 850.25 mi (1,368.34 km) |
| Irthlingborough to Moita | 1,026.45 mi (1,651.91 km) |
| Irthlingborough to Moncao | 797.64 mi (1,283.68 km) |
