| Waltham Cross to Orbetello | 827.71 mi (1,332.08 km) |
| Waltham Cross to Oria | 1,140.74 mi (1,835.84 km) |
| Waltham Cross to Oristano | 912.36 mi (1,468.30 km) |
| Waltham Cross to Orta Nova | 1,031.49 mi (1,660.03 km) |
| Waltham Cross to Orte | 862.46 mi (1,388.00 km) |
| Waltham Cross to Ortona | 934.06 mi (1,503.22 km) |
| Waltham Cross to Orvieto | 839.78 mi (1,351.49 km) |
| Waltham Cross to Orzinuovi | 628.63 mi (1,011.68 km) |
| Waltham Cross to Osimo | 844.91 mi (1,359.75 km) |
| Waltham Cross to Ospitaletto | 625.46 mi (1,006.58 km) |
| Waltham Cross to Ostuni | 1,126.95 mi (1,813.66 km) |
| Waltham Cross to Ottaviano | 1,016.57 mi (1,636.01 km) |
| Waltham Cross to Ovada | 629.24 mi (1,012.66 km) |
| Waltham Cross to Ozieri | 879.09 mi (1,414.76 km) |
| Waltham Cross to Paceco | 1,126.28 mi (1,812.58 km) |
