| South Houston to Montalegre | 4,764.95 mi (7,668.45 km) |
| South Houston to Montemor-o-Novo | 4,826.27 mi (7,767.14 km) |
| South Houston to Montemor-o-Velho | 4,763.85 mi (7,666.68 km) |
| South Houston to Montijo | 4,791.28 mi (7,710.83 km) |
| South Houston to Mortagua | 4,779.06 mi (7,691.16 km) |
| South Houston to Moura | 4,878.36 mi (7,850.96 km) |
| South Houston to Murtosa | 4,751.91 mi (7,647.46 km) |
| South Houston to Nazare | 4,759.41 mi (7,659.53 km) |
| South Houston to Nelas | 4,795.61 mi (7,717.78 km) |
| South Houston to Obidos | 4,761.07 mi (7,662.20 km) |
| South Houston to Odemira | 4,833.56 mi (7,778.86 km) |
| South Houston to Odivelas | 4,774.54 mi (7,683.88 km) |
| South Houston to Oeiras | 4,770.44 mi (7,677.28 km) |
| South Houston to Olhao | 4,888.64 mi (7,867.51 km) |
| South Houston to Oliveira de Azemeis | 4,756.91 mi (7,655.51 km) |
