| Middle Island to Mangualde | 3,328.32 mi (5,356.42 km) |
| Middle Island to Marco de Canavezes | 3,294.18 mi (5,301.47 km) |
| Middle Island to Marinha Grande | 3,294.52 mi (5,302.02 km) |
| Middle Island to Massama | 3,305.21 mi (5,319.22 km) |
| Middle Island to Matosinhos | 3,267.70 mi (5,258.86 km) |
| Middle Island to Mealhada | 3,300.92 mi (5,312.31 km) |
| Middle Island to Melgaco | 3,264.55 mi (5,253.79 km) |
| Middle Island to Melres | 3,285.20 mi (5,287.02 km) |
| Middle Island to Mira | 3,285.84 mi (5,288.04 km) |
| Middle Island to Miranda do Corvo | 3,314.23 mi (5,333.74 km) |
| Middle Island to Mirandela | 3,332.69 mi (5,363.45 km) |
| Middle Island to Mogadouro | 3,358.97 mi (5,405.75 km) |
| Middle Island to Moimenta da Beira | 3,325.37 mi (5,351.67 km) |
| Middle Island to Moita | 3,322.57 mi (5,347.16 km) |
| Middle Island to Moncao | 3,255.47 mi (5,239.17 km) |
