| South Houston to Mangualde | 4,797.67 mi (7,721.10 km) |
| South Houston to Marco de Canavezes | 4,763.96 mi (7,666.85 km) |
| South Houston to Marinha Grande | 4,762.18 mi (7,663.98 km) |
| South Houston to Massama | 4,770.65 mi (7,677.61 km) |
| South Houston to Matosinhos | 4,737.33 mi (7,624.00 km) |
| South Houston to Mealhada | 4,769.75 mi (7,676.18 km) |
| South Houston to Melgaco | 4,734.84 mi (7,619.98 km) |
| South Houston to Melres | 4,754.81 mi (7,652.13 km) |
| South Houston to Mira | 4,754.63 mi (7,651.83 km) |
| South Houston to Miranda do Corvo | 4,782.73 mi (7,697.07 km) |
| South Houston to Mirandela | 4,802.85 mi (7,729.45 km) |
| South Houston to Mogadouro | 4,829.13 mi (7,771.74 km) |
| South Houston to Moimenta da Beira | 4,795.12 mi (7,717.00 km) |
| South Houston to Moita | 4,787.98 mi (7,705.51 km) |
| South Houston to Moncao | 4,725.72 mi (7,605.30 km) |
