| Upper Grand Lagoon to Mangualde | 4,309.28 mi (6,935.12 km) |
| Upper Grand Lagoon to Marco de Canavezes | 4,278.10 mi (6,884.93 km) |
| Upper Grand Lagoon to Marinha Grande | 4,267.71 mi (6,868.22 km) |
| Upper Grand Lagoon to Massama | 4,270.73 mi (6,873.08 km) |
| Upper Grand Lagoon to Matosinhos | 4,250.71 mi (6,840.85 km) |
| Upper Grand Lagoon to Mealhada | 4,279.23 mi (6,886.76 km) |
| Upper Grand Lagoon to Melgaco | 4,253.91 mi (6,846.01 km) |
| Upper Grand Lagoon to Melres | 4,267.98 mi (6,868.64 km) |
| Upper Grand Lagoon to Mira | 4,263.97 mi (6,862.20 km) |
| Upper Grand Lagoon to Miranda do Corvo | 4,290.90 mi (6,905.54 km) |
| Upper Grand Lagoon to Mirandela | 4,320.01 mi (6,952.38 km) |
| Upper Grand Lagoon to Mogadouro | 4,346.14 mi (6,994.44 km) |
| Upper Grand Lagoon to Moimenta da Beira | 4,308.93 mi (6,934.56 km) |
| Upper Grand Lagoon to Moita | 4,287.94 mi (6,900.78 km) |
| Upper Grand Lagoon to Moncao | 4,244.25 mi (6,830.47 km) |
