| Hardinxveld-Giessendam to Orbetello | 713.27 mi (1,147.90 km) |
| Hardinxveld-Giessendam to Oria | 990.27 mi (1,593.69 km) |
| Hardinxveld-Giessendam to Oristano | 842.30 mi (1,355.55 km) |
| Hardinxveld-Giessendam to Orta Nova | 887.80 mi (1,428.77 km) |
| Hardinxveld-Giessendam to Orte | 736.59 mi (1,185.43 km) |
| Hardinxveld-Giessendam to Ortona | 792.53 mi (1,275.45 km) |
| Hardinxveld-Giessendam to Orvieto | 714.42 mi (1,149.75 km) |
| Hardinxveld-Giessendam to Orzinuovi | 500.55 mi (805.56 km) |
| Hardinxveld-Giessendam to Osimo | 701.53 mi (1,129.00 km) |
| Hardinxveld-Giessendam to Ospitaletto | 493.95 mi (794.94 km) |
| Hardinxveld-Giessendam to Ostuni | 975.42 mi (1,569.78 km) |
| Hardinxveld-Giessendam to Ottaviano | 884.75 mi (1,423.87 km) |
| Hardinxveld-Giessendam to Ovada | 525.87 mi (846.31 km) |
| Hardinxveld-Giessendam to Ozieri | 800.91 mi (1,288.94 km) |
| Hardinxveld-Giessendam to Paceco | 1,026.31 mi (1,651.68 km) |
