| Mountain Ash to Octeville | 161.03 mi (259.15 km) |
| Mountain Ash to Oignies | 288.94 mi (465.01 km) |
| Mountain Ash to Oissel | 254.31 mi (409.27 km) |
| Mountain Ash to Olivet | 353.48 mi (568.87 km) |
| Mountain Ash to Ollioules | 729.83 mi (1,174.54 km) |
| Mountain Ash to Olonne-sur-Mer | 362.83 mi (583.92 km) |
| Mountain Ash to Oloron-Sainte-Marie | 600.43 mi (966.31 km) |
| Mountain Ash to Onet Village | 575.46 mi (926.12 km) |
| Mountain Ash to Onnaing | 315.92 mi (508.42 km) |
| Mountain Ash to Orange | 643.70 mi (1,035.94 km) |
| Mountain Ash to Orchies | 299.24 mi (481.57 km) |
| Mountain Ash to Orleans | 351.68 mi (565.98 km) |
| Mountain Ash to Orly | 325.91 mi (524.50 km) |
| Mountain Ash to Ormesson-sur-Marne | 329.11 mi (529.65 km) |
| Mountain Ash to Orsay | 320.98 mi (516.57 km) |
