| North Potomac to Octeville | 3,643.64 mi (5,863.87 km) |
| North Potomac to Oignies | 3,816.43 mi (6,141.95 km) |
| North Potomac to Oissel | 3,765.67 mi (6,060.27 km) |
| North Potomac to Olivet | 3,837.81 mi (6,176.36 km) |
| North Potomac to Ollioules | 4,148.39 mi (6,676.19 km) |
| North Potomac to Olonne-sur-Mer | 3,711.86 mi (5,973.67 km) |
| North Potomac to Oloron-Sainte-Marie | 3,853.56 mi (6,201.71 km) |
| North Potomac to Onet Village | 3,965.33 mi (6,381.58 km) |
| North Potomac to Onnaing | 3,843.23 mi (6,185.09 km) |
| North Potomac to Orange | 4,071.05 mi (6,551.72 km) |
| North Potomac to Orchies | 3,826.54 mi (6,158.23 km) |
| North Potomac to Orleans | 3,837.15 mi (6,175.30 km) |
| North Potomac to Orly | 3,835.68 mi (6,172.93 km) |
| North Potomac to Ormesson-sur-Marne | 3,840.72 mi (6,181.04 km) |
| North Potomac to Orsay | 3,828.20 mi (6,160.89 km) |
