| Porsgrunn to Oswego (Illinois) | 4,067.19 mi (6,545.51 km) |
| Porsgrunn to Oswego (New York) | 3,596.92 mi (5,788.69 km) |
| Porsgrunn to Otsego (Minnesota) | 4,024.02 mi (6,476.03 km) |
| Porsgrunn to Ottawa (Illinois) | 4,100.42 mi (6,599.00 km) |
| Porsgrunn to Ottawa (Kansas) | 4,451.03 mi (7,163.24 km) |
| Porsgrunn to Ottumwa (Iowa) | 4,227.93 mi (6,804.19 km) |
| Porsgrunn to Overland (Missouri) | 4,297.38 mi (6,915.97 km) |
| Porsgrunn to Overland Park (Kansas) | 4,417.33 mi (7,109.00 km) |
| Porsgrunn to Overlea (Maryland) | 3,815.34 mi (6,140.20 km) |
| Porsgrunn to Oviedo (Florida) | 4,569.74 mi (7,354.28 km) |
| Porsgrunn to Owasso (Oklahoma) | 4,601.97 mi (7,406.16 km) |
| Porsgrunn to Owatonna (Minnesota) | 4,078.64 mi (6,563.94 km) |
| Porsgrunn to Owensboro (Kentucky) | 4,248.81 mi (6,837.80 km) |
| Porsgrunn to Owings Mills (Maryland) | 3,821.90 mi (6,150.75 km) |
| Porsgrunn to Owosso (Michigan) | 3,866.32 mi (6,222.24 km) |
