| Barrhead to Orbetello | 1,156.26 mi (1,860.82 km) |
| Barrhead to Oria | 1,453.30 mi (2,338.85 km) |
| Barrhead to Oristano | 1,247.65 mi (2,007.89 km) |
| Barrhead to Orta Nova | 1,348.16 mi (2,169.65 km) |
| Barrhead to Orte | 1,187.19 mi (1,910.59 km) |
| Barrhead to Ortona | 1,251.64 mi (2,014.32 km) |
| Barrhead to Orvieto | 1,164.58 mi (1,874.22 km) |
| Barrhead to Orzinuovi | 950.70 mi (1,530.00 km) |
| Barrhead to Osimo | 1,161.04 mi (1,868.52 km) |
| Barrhead to Ospitaletto | 946.02 mi (1,522.47 km) |
| Barrhead to Ostuni | 1,438.73 mi (2,315.41 km) |
| Barrhead to Ottaviano | 1,339.43 mi (2,155.61 km) |
| Barrhead to Ovada | 959.38 mi (1,543.97 km) |
| Barrhead to Ozieri | 1,214.15 mi (1,953.98 km) |
| Barrhead to Paceco | 1,459.39 mi (2,348.67 km) |
