| Big Spring to Mangualde | 4,989.21 mi (8,029.35 km) |
| Big Spring to Marco de Canavezes | 4,952.77 mi (7,970.71 km) |
| Big Spring to Marinha Grande | 4,961.40 mi (7,984.60 km) |
| Big Spring to Massama | 4,976.58 mi (8,009.03 km) |
| Big Spring to Matosinhos | 4,927.29 mi (7,929.71 km) |
| Big Spring to Mealhada | 4,964.10 mi (7,988.95 km) |
| Big Spring to Melgaco | 4,918.10 mi (7,914.92 km) |
| Big Spring to Melres | 4,944.86 mi (7,957.99 km) |
| Big Spring to Mira | 4,949.27 mi (7,965.07 km) |
| Big Spring to Miranda do Corvo | 4,978.56 mi (8,012.22 km) |
| Big Spring to Mirandela | 4,987.75 mi (8,027.02 km) |
| Big Spring to Mogadouro | 5,013.97 mi (8,069.20 km) |
| Big Spring to Moimenta da Beira | 4,984.04 mi (8,021.04 km) |
| Big Spring to Moita | 4,993.93 mi (8,036.95 km) |
| Big Spring to Moncao | 4,909.69 mi (7,901.38 km) |
