| Portland to Octeville | 4,970.63 mi (7,999.46 km) |
| Portland to Oignies | 5,050.88 mi (8,128.60 km) |
| Portland to Oissel | 5,062.17 mi (8,146.77 km) |
| Portland to Olivet | 5,165.92 mi (8,313.75 km) |
| Portland to Ollioules | 5,542.68 mi (8,920.09 km) |
| Portland to Olonne-sur-Mer | 5,133.08 mi (8,260.90 km) |
| Portland to Oloron-Sainte-Marie | 5,350.11 mi (8,610.17 km) |
| Portland to Onet Village | 5,380.46 mi (8,659.01 km) |
| Portland to Onnaing | 5,071.17 mi (8,161.25 km) |
| Portland to Orange | 5,456.45 mi (8,781.31 km) |
| Portland to Orchies | 5,057.12 mi (8,138.64 km) |
| Portland to Orleans | 5,164.02 mi (8,310.69 km) |
| Portland to Orly | 5,130.64 mi (8,256.97 km) |
| Portland to Ormesson-sur-Marne | 5,132.26 mi (8,259.57 km) |
| Portland to Orsay | 5,127.60 mi (8,252.07 km) |
