| Porsgrunn to Octeville | 796.81 mi (1,282.34 km) |
| Porsgrunn to Oignies | 653.81 mi (1,052.21 km) |
| Porsgrunn to Oissel | 758.32 mi (1,220.40 km) |
| Porsgrunn to Olivet | 839.75 mi (1,351.45 km) |
| Porsgrunn to Ollioules | 1,116.02 mi (1,796.07 km) |
| Porsgrunn to Olonne-sur-Mer | 989.45 mi (1,592.37 km) |
| Porsgrunn to Oloron-Sainte-Marie | 1,184.24 mi (1,905.85 km) |
| Porsgrunn to Onet Village | 1,062.19 mi (1,709.43 km) |
| Porsgrunn to Onnaing | 649.77 mi (1,045.70 km) |
| Porsgrunn to Orange | 1,055.26 mi (1,698.28 km) |
| Porsgrunn to Orchies | 649.49 mi (1,045.26 km) |
| Porsgrunn to Orleans | 837.11 mi (1,347.20 km) |
| Porsgrunn to Orly | 774.89 mi (1,247.06 km) |
| Porsgrunn to Ormesson-sur-Marne | 769.95 mi (1,239.11 km) |
| Porsgrunn to Orsay | 781.04 mi (1,256.96 km) |
