| Porsgrunn to Montemor-o-Novo | 1,620.12 mi (2,607.32 km) |
| Porsgrunn to Montemor-o-Velho | 1,534.93 mi (2,470.23 km) |
| Porsgrunn to Montijo | 1,632.86 mi (2,627.84 km) |
| Porsgrunn to Mortagua | 1,508.15 mi (2,427.13 km) |
| Porsgrunn to Moura | 1,636.97 mi (2,634.45 km) |
| Porsgrunn to Murtosa | 1,498.50 mi (2,411.60 km) |
| Porsgrunn to Nazare | 1,579.02 mi (2,541.18 km) |
| Porsgrunn to Nelas | 1,494.41 mi (2,405.02 km) |
| Porsgrunn to Obidos | 1,596.21 mi (2,568.86 km) |
| Porsgrunn to Odemira | 1,696.79 mi (2,730.72 km) |
| Porsgrunn to Odivelas | 1,632.33 mi (2,626.98 km) |
| Porsgrunn to Oeiras | 1,642.12 mi (2,642.74 km) |
| Porsgrunn to Olhao | 1,715.94 mi (2,761.54 km) |
| Porsgrunn to Oliveira de Azemeis | 1,488.25 mi (2,395.11 km) |
| Porsgrunn to Oliveira de Frades | 1,489.33 mi (2,396.84 km) |
