| South River to Mangualde | 3,409.34 mi (5,486.79 km) |
| South River to Marco de Canavezes | 3,375.18 mi (5,431.83 km) |
| South River to Marinha Grande | 3,375.53 mi (5,432.40 km) |
| South River to Massama | 3,386.17 mi (5,449.52 km) |
| South River to Matosinhos | 3,348.71 mi (5,389.22 km) |
| South River to Mealhada | 3,381.94 mi (5,442.70 km) |
| South River to Melgaco | 3,345.50 mi (5,384.06 km) |
| South River to Melres | 3,366.21 mi (5,417.39 km) |
| South River to Mira | 3,366.86 mi (5,418.43 km) |
| South River to Miranda do Corvo | 3,395.25 mi (5,464.13 km) |
| South River to Mirandela | 3,413.66 mi (5,493.75 km) |
| South River to Mogadouro | 3,439.94 mi (5,536.05 km) |
| South River to Moimenta da Beira | 3,406.37 mi (5,482.03 km) |
| South River to Moita | 3,403.53 mi (5,477.46 km) |
| South River to Moncao | 3,336.42 mi (5,369.45 km) |
