| Silver Spring to Orbetello | 4,404.30 mi (7,088.03 km) |
| Silver Spring to Oria | 4,757.17 mi (7,655.92 km) |
| Silver Spring to Oristano | 4,373.44 mi (7,038.37 km) |
| Silver Spring to Orta Nova | 4,641.78 mi (7,470.22 km) |
| Silver Spring to Orte | 4,455.24 mi (7,170.02 km) |
| Silver Spring to Ortona | 4,547.17 mi (7,317.96 km) |
| Silver Spring to Orvieto | 4,434.11 mi (7,136.02 km) |
| Silver Spring to Orzinuovi | 4,249.44 mi (6,838.81 km) |
| Silver Spring to Osimo | 4,466.96 mi (7,188.88 km) |
| Silver Spring to Ospitaletto | 4,250.39 mi (6,840.34 km) |
| Silver Spring to Ostuni | 4,746.02 mi (7,637.98 km) |
| Silver Spring to Ottaviano | 4,605.35 mi (7,411.59 km) |
| Silver Spring to Ovada | 4,218.41 mi (6,788.87 km) |
| Silver Spring to Ozieri | 4,368.96 mi (7,031.17 km) |
| Silver Spring to Paceco | 4,624.15 mi (7,441.85 km) |
