| Olton to Mangualde | 864.51 mi (1,391.30 km) |
| Olton to Marco de Canavezes | 832.67 mi (1,340.06 km) |
| Olton to Marinha Grande | 939.69 mi (1,512.28 km) |
| Olton to Massama | 1,010.56 mi (1,626.34 km) |
| Olton to Matosinhos | 842.24 mi (1,355.46 km) |
| Olton to Mealhada | 890.07 mi (1,432.42 km) |
| Olton to Melgaco | 774.00 mi (1,245.64 km) |
| Olton to Melres | 844.54 mi (1,359.15 km) |
| Olton to Mira | 891.61 mi (1,434.90 km) |
| Olton to Miranda do Corvo | 906.76 mi (1,459.29 km) |
| Olton to Mirandela | 797.51 mi (1,283.47 km) |
| Olton to Mogadouro | 801.04 mi (1,289.16 km) |
| Olton to Moimenta da Beira | 837.44 mi (1,347.74 km) |
| Olton to Moita | 1,012.75 mi (1,629.87 km) |
| Olton to Moncao | 780.71 mi (1,256.43 km) |
