| Markham to Orbetello | 4,749.41 mi (7,643.43 km) |
| Markham to Oria | 5,091.16 mi (8,193.43 km) |
| Markham to Oristano | 4,747.10 mi (7,639.73 km) |
| Markham to Orta Nova | 4,977.66 mi (8,010.77 km) |
| Markham to Orte | 4,795.77 mi (7,718.04 km) |
| Markham to Ortona | 4,880.75 mi (7,854.81 km) |
| Markham to Orvieto | 4,773.73 mi (7,682.58 km) |
| Markham to Orzinuovi | 4,576.02 mi (7,364.39 km) |
| Markham to Osimo | 4,795.54 mi (7,717.67 km) |
| Markham to Ospitaletto | 4,575.21 mi (7,363.09 km) |
| Markham to Ostuni | 5,078.56 mi (8,173.16 km) |
| Markham to Ottaviano | 4,949.64 mi (7,965.68 km) |
| Markham to Ovada | 4,555.67 mi (7,331.64 km) |
| Markham to Ozieri | 4,736.14 mi (7,622.09 km) |
| Markham to Paceco | 4,996.34 mi (8,040.84 km) |
