| Porsgrunn to Oberkirch | 734.11 mi (1,181.44 km) |
| Porsgrunn to Obernburg am Main | 641.28 mi (1,032.04 km) |
| Porsgrunn to Obernkirchen | 473.79 mi (762.49 km) |
| Porsgrunn to Oberschleissheim | 754.50 mi (1,214.25 km) |
| Porsgrunn to Oberstdorf | 809.13 mi (1,302.17 km) |
| Porsgrunn to Obertraubling | 708.21 mi (1,139.75 km) |
| Porsgrunn to Obertshausen | 626.19 mi (1,007.75 km) |
| Porsgrunn to Oberursel | 617.42 mi (993.64 km) |
| Porsgrunn to Ochsenfurt | 654.16 mi (1,052.78 km) |
| Porsgrunn to Ochsenhausen | 763.09 mi (1,228.07 km) |
| Porsgrunn to Ochtrup | 487.34 mi (784.30 km) |
| Porsgrunn to Odenthal | 567.67 mi (913.57 km) |
| Porsgrunn to Oelde | 506.82 mi (815.64 km) |
| Porsgrunn to Oelsnitz | 608.85 mi (979.86 km) |
| Porsgrunn to Oer-Erkenschwick | 525.22 mi (845.25 km) |
