| Catonsville to Octeville | 3,615.54 mi (5,818.65 km) |
| Catonsville to Oignies | 3,788.63 mi (6,097.21 km) |
| Catonsville to Oissel | 3,737.63 mi (6,015.13 km) |
| Catonsville to Olivet | 3,809.59 mi (6,130.94 km) |
| Catonsville to Ollioules | 4,119.81 mi (6,630.19 km) |
| Catonsville to Olonne-sur-Mer | 3,683.37 mi (5,927.81 km) |
| Catonsville to Oloron-Sainte-Marie | 3,824.81 mi (6,155.44 km) |
| Catonsville to Onet Village | 3,936.75 mi (6,335.59 km) |
| Catonsville to Onnaing | 3,815.45 mi (6,140.37 km) |
| Catonsville to Orange | 4,042.52 mi (6,505.81 km) |
| Catonsville to Orchies | 3,798.75 mi (6,113.50 km) |
| Catonsville to Orleans | 3,808.94 mi (6,129.89 km) |
| Catonsville to Orly | 3,807.59 mi (6,127.73 km) |
| Catonsville to Ormesson-sur-Marne | 3,812.65 mi (6,135.86 km) |
| Catonsville to Orsay | 3,800.10 mi (6,115.67 km) |
