| Idanha-a-Nova to Orbetello | 972.94 mi (1,565.79 km) |
| Idanha-a-Nova to Oria | 1,308.40 mi (2,105.66 km) |
| Idanha-a-Nova to Oristano | 837.57 mi (1,347.95 km) |
| Idanha-a-Nova to Orta Nova | 1,203.70 mi (1,937.17 km) |
| Idanha-a-Nova to Orte | 1,032.74 mi (1,662.04 km) |
| Idanha-a-Nova to Ortona | 1,135.12 mi (1,826.79 km) |
| Idanha-a-Nova to Orvieto | 1,019.92 mi (1,641.40 km) |
| Idanha-a-Nova to Orzinuovi | 948.52 mi (1,526.50 km) |
| Idanha-a-Nova to Osimo | 1,093.67 mi (1,760.09 km) |
| Idanha-a-Nova to Ospitaletto | 958.24 mi (1,542.14 km) |
| Idanha-a-Nova to Ostuni | 1,304.10 mi (2,098.74 km) |
| Idanha-a-Nova to Ottaviano | 1,141.54 mi (1,837.12 km) |
| Idanha-a-Nova to Ovada | 873.08 mi (1,405.08 km) |
| Idanha-a-Nova to Ozieri | 856.24 mi (1,377.99 km) |
| Idanha-a-Nova to Paceco | 1,069.15 mi (1,720.64 km) |
