| Mount Holly to Orbetello | 4,731.83 mi (7,615.15 km) |
| Mount Holly to Oria | 5,085.87 mi (8,184.92 km) |
| Mount Holly to Oristano | 4,695.74 mi (7,557.06 km) |
| Mount Holly to Orta Nova | 4,970.37 mi (7,999.04 km) |
| Mount Holly to Orte | 4,783.42 mi (7,698.16 km) |
| Mount Holly to Ortona | 4,876.23 mi (7,847.54 km) |
| Mount Holly to Orvieto | 4,762.46 mi (7,664.44 km) |
| Mount Holly to Orzinuovi | 4,579.87 mi (7,370.59 km) |
| Mount Holly to Osimo | 4,796.83 mi (7,719.76 km) |
| Mount Holly to Ospitaletto | 4,581.05 mi (7,372.48 km) |
| Mount Holly to Ostuni | 5,074.96 mi (8,167.35 km) |
| Mount Holly to Ottaviano | 4,932.69 mi (7,938.40 km) |
| Mount Holly to Ovada | 4,547.43 mi (7,318.38 km) |
| Mount Holly to Ozieri | 4,692.60 mi (7,552.02 km) |
| Mount Holly to Paceco | 4,946.26 mi (7,960.24 km) |
