| Romeoville to Montalegre | 3,975.33 mi (6,397.67 km) |
| Romeoville to Montemor-o-Novo | 4,065.32 mi (6,542.50 km) |
| Romeoville to Montemor-o-Velho | 3,991.07 mi (6,423.01 km) |
| Romeoville to Montijo | 4,032.41 mi (6,489.53 km) |
| Romeoville to Mortagua | 4,002.53 mi (6,441.46 km) |
| Romeoville to Moura | 4,119.29 mi (6,629.36 km) |
| Romeoville to Murtosa | 3,974.05 mi (6,395.61 km) |
| Romeoville to Nazare | 3,992.88 mi (6,425.92 km) |
| Romeoville to Nelas | 4,017.15 mi (6,464.98 km) |
| Romeoville to Obidos | 3,997.00 mi (6,432.55 km) |
| Romeoville to Odemira | 4,083.73 mi (6,572.13 km) |
| Romeoville to Odivelas | 4,015.66 mi (6,462.58 km) |
| Romeoville to Oeiras | 4,013.01 mi (6,458.31 km) |
| Romeoville to Olhao | 4,140.95 mi (6,664.22 km) |
| Romeoville to Oliveira de Azemeis | 3,977.64 mi (6,401.40 km) |
