| Madrid to Orbetello | 784.17 mi (1,262.01 km) |
| Madrid to Oria | 1,118.96 mi (1,800.80 km) |
| Madrid to Oristano | 649.65 mi (1,045.50 km) |
| Madrid to Orta Nova | 1,014.16 mi (1,632.14 km) |
| Madrid to Orte | 843.92 mi (1,358.16 km) |
| Madrid to Ortona | 946.10 mi (1,522.60 km) |
| Madrid to Orvieto | 831.48 mi (1,338.14 km) |
| Madrid to Orzinuovi | 769.85 mi (1,238.95 km) |
| Madrid to Osimo | 906.42 mi (1,458.74 km) |
| Madrid to Ospitaletto | 780.15 mi (1,255.53 km) |
| Madrid to Ostuni | 1,114.59 mi (1,793.77 km) |
| Madrid to Ottaviano | 952.06 mi (1,532.19 km) |
| Madrid to Ovada | 692.24 mi (1,114.05 km) |
| Madrid to Ozieri | 667.10 mi (1,073.60 km) |
| Madrid to Paceco | 885.01 mi (1,424.29 km) |
