| Gretna to Mangualde | 4,533.77 mi (7,296.41 km) |
| Gretna to Marco de Canavezes | 4,501.44 mi (7,244.36 km) |
| Gretna to Marinha Grande | 4,494.87 mi (7,233.80 km) |
| Gretna to Massama | 4,500.31 mi (7,242.56 km) |
| Gretna to Matosinhos | 4,474.36 mi (7,200.79 km) |
| Gretna to Mealhada | 4,504.65 mi (7,249.53 km) |
| Gretna to Melgaco | 4,475.03 mi (7,201.86 km) |
| Gretna to Melres | 4,491.74 mi (7,228.76 km) |
| Gretna to Mira | 4,489.43 mi (7,225.05 km) |
| Gretna to Miranda do Corvo | 4,516.91 mi (7,269.27 km) |
| Gretna to Mirandela | 4,542.04 mi (7,309.71 km) |
| Gretna to Mogadouro | 4,568.26 mi (7,351.90 km) |
| Gretna to Moimenta da Beira | 4,532.44 mi (7,294.26 km) |
| Gretna to Moita | 4,517.59 mi (7,270.37 km) |
| Gretna to Moncao | 4,465.60 mi (7,186.69 km) |
