| Glenmont to Orbetello | 4,402.81 mi (7,085.64 km) |
| Glenmont to Oria | 4,755.60 mi (7,653.40 km) |
| Glenmont to Oristano | 4,372.24 mi (7,036.44 km) |
| Glenmont to Orta Nova | 4,640.22 mi (7,467.72 km) |
| Glenmont to Orte | 4,453.72 mi (7,167.56 km) |
| Glenmont to Ortona | 4,545.58 mi (7,315.41 km) |
| Glenmont to Orvieto | 4,432.58 mi (7,133.54 km) |
| Glenmont to Orzinuovi | 4,247.76 mi (6,836.11 km) |
| Glenmont to Osimo | 4,465.32 mi (7,186.24 km) |
| Glenmont to Ospitaletto | 4,248.70 mi (6,837.62 km) |
| Glenmont to Ostuni | 4,744.44 mi (7,635.44 km) |
| Glenmont to Ottaviano | 4,603.87 mi (7,409.22 km) |
| Glenmont to Ovada | 4,216.83 mi (6,786.33 km) |
| Glenmont to Ozieri | 4,367.70 mi (7,029.13 km) |
| Glenmont to Paceco | 4,622.96 mi (7,439.94 km) |
