| Houston to Octeville | 4,837.75 mi (7,785.61 km) |
| Houston to Oignies | 5,001.33 mi (8,048.86 km) |
| Houston to Oissel | 4,957.99 mi (7,979.11 km) |
| Houston to Olivet | 5,035.00 mi (8,103.04 km) |
| Houston to Ollioules | 5,355.37 mi (8,618.63 km) |
| Houston to Olonne-sur-Mer | 4,916.78 mi (7,912.79 km) |
| Houston to Oloron-Sainte-Marie | 5,064.89 mi (8,151.15 km) |
| Houston to Onet Village | 5,172.25 mi (8,323.94 km) |
| Houston to Onnaing | 5,027.71 mi (8,091.32 km) |
| Houston to Orange | 5,276.60 mi (8,491.87 km) |
| Houston to Orchies | 5,011.08 mi (8,064.56 km) |
| Houston to Orleans | 5,034.19 mi (8,101.74 km) |
| Houston to Orly | 5,028.93 mi (8,093.28 km) |
| Houston to Ormesson-sur-Marne | 5,033.63 mi (8,100.84 km) |
| Houston to Orsay | 5,021.88 mi (8,081.93 km) |
