| Grinon to Mangualde | 207.48 mi (333.90 km) |
| Grinon to Marco de Canavezes | 234.91 mi (378.04 km) |
| Grinon to Marinha Grande | 271.00 mi (436.14 km) |
| Grinon to Massama | 306.29 mi (492.93 km) |
| Grinon to Matosinhos | 262.64 mi (422.68 km) |
| Grinon to Mealhada | 242.64 mi (390.50 km) |
| Grinon to Melgaco | 264.54 mi (425.73 km) |
| Grinon to Melres | 245.64 mi (395.31 km) |
| Grinon to Mira | 257.63 mi (414.62 km) |
| Grinon to Miranda do Corvo | 236.86 mi (381.18 km) |
| Grinon to Mirandela | 194.92 mi (313.70 km) |
| Grinon to Mogadouro | 168.66 mi (271.43 km) |
| Grinon to Moimenta da Beira | 204.34 mi (328.86 km) |
| Grinon to Moita | 294.49 mi (473.94 km) |
| Grinon to Moncao | 272.87 mi (439.14 km) |
