| Witham to Mangualde | 870.12 mi (1,400.33 km) |
| Witham to Marco de Canavezes | 842.76 mi (1,356.29 km) |
| Witham to Marinha Grande | 949.80 mi (1,528.56 km) |
| Witham to Massama | 1,019.68 mi (1,641.02 km) |
| Witham to Matosinhos | 855.84 mi (1,377.35 km) |
| Witham to Mealhada | 899.30 mi (1,447.28 km) |
| Witham to Melgaco | 788.47 mi (1,268.93 km) |
| Witham to Melres | 855.81 mi (1,377.29 km) |
| Witham to Mira | 902.74 mi (1,452.83 km) |
| Witham to Miranda do Corvo | 914.36 mi (1,471.52 km) |
| Witham to Mirandela | 802.20 mi (1,291.02 km) |
| Witham to Mogadouro | 802.02 mi (1,290.73 km) |
| Witham to Moimenta da Beira | 843.32 mi (1,357.20 km) |
| Witham to Moita | 1,019.94 mi (1,641.43 km) |
| Witham to Moncao | 796.42 mi (1,281.71 km) |
