| Port Huron to Octeville | 3,694.63 mi (5,945.93 km) |
| Port Huron to Oignies | 3,851.41 mi (6,198.24 km) |
| Port Huron to Oissel | 3,813.02 mi (6,136.46 km) |
| Port Huron to Olivet | 3,894.07 mi (6,266.90 km) |
| Port Huron to Ollioules | 4,226.73 mi (6,802.27 km) |
| Port Huron to Olonne-sur-Mer | 3,786.20 mi (6,093.31 km) |
| Port Huron to Oloron-Sainte-Marie | 3,948.75 mi (6,354.90 km) |
| Port Huron to Onet Village | 4,044.25 mi (6,508.60 km) |
| Port Huron to Onnaing | 3,877.51 mi (6,240.24 km) |
| Port Huron to Orange | 4,145.68 mi (6,671.82 km) |
| Port Huron to Orchies | 3,860.95 mi (6,213.59 km) |
| Port Huron to Orleans | 3,893.11 mi (6,265.36 km) |
| Port Huron to Orly | 3,884.49 mi (6,251.49 km) |
| Port Huron to Ormesson-sur-Marne | 3,888.91 mi (6,258.59 km) |
| Port Huron to Orsay | 3,877.81 mi (6,240.73 km) |
