| Grefrath to Marco de Canavezes | 982.13 mi (1,580.59 km) |
| Grefrath to Marinha Grande | 1,085.28 mi (1,746.59 km) |
| Grefrath to Massama | 1,151.24 mi (1,852.74 km) |
| Grefrath to Matosinhos | 1,000.51 mi (1,610.17 km) |
| Grefrath to Mealhada | 1,035.04 mi (1,665.74 km) |
| Grefrath to Melgaco | 937.30 mi (1,508.43 km) |
| Grefrath to Melres | 996.64 mi (1,603.93 km) |
| Grefrath to Mira | 1,041.59 mi (1,676.27 km) |
| Grefrath to Miranda do Corvo | 1,046.77 mi (1,684.61 km) |
| Grefrath to Mirandela | 934.25 mi (1,503.54 km) |
| Grefrath to Mogadouro | 927.67 mi (1,492.94 km) |
| Grefrath to Moimenta da Beira | 975.57 mi (1,570.03 km) |
| Grefrath to Moita | 1,148.09 mi (1,847.68 km) |
| Grefrath to Moncao | 946.87 mi (1,523.85 km) |
| Grefrath to Montalegre | 936.37 mi (1,506.94 km) |
