| Castle Rock to Mangualde | 4,843.22 mi (7,794.41 km) |
| Castle Rock to Marco de Canavezes | 4,803.58 mi (7,730.61 km) |
| Castle Rock to Marinha Grande | 4,826.64 mi (7,767.72 km) |
| Castle Rock to Massama | 4,851.13 mi (7,807.14 km) |
| Castle Rock to Matosinhos | 4,780.10 mi (7,692.83 km) |
| Castle Rock to Mealhada | 4,822.44 mi (7,760.96 km) |
| Castle Rock to Melgaco | 4,761.83 mi (7,663.42 km) |
| Castle Rock to Melres | 4,797.52 mi (7,720.86 km) |
| Castle Rock to Mira | 4,808.25 mi (7,738.12 km) |
| Castle Rock to Miranda do Corvo | 4,838.74 mi (7,787.19 km) |
| Castle Rock to Mirandela | 4,832.63 mi (7,777.36 km) |
| Castle Rock to Mogadouro | 4,858.34 mi (7,818.75 km) |
| Castle Rock to Moimenta da Beira | 4,834.52 mi (7,780.41 km) |
| Castle Rock to Moita | 4,868.23 mi (7,834.65 km) |
| Castle Rock to Moncao | 4,754.53 mi (7,651.67 km) |
