| Glenn Dale to Octeville | 3,630.07 mi (5,842.03 km) |
| Glenn Dale to Oignies | 3,803.67 mi (6,121.41 km) |
| Glenn Dale to Oissel | 3,752.25 mi (6,038.67 km) |
| Glenn Dale to Olivet | 3,823.88 mi (6,153.94 km) |
| Glenn Dale to Ollioules | 4,133.18 mi (6,651.71 km) |
| Glenn Dale to Olonne-sur-Mer | 3,697.02 mi (5,949.77 km) |
| Glenn Dale to Oloron-Sainte-Marie | 3,837.58 mi (6,175.99 km) |
| Glenn Dale to Onet Village | 3,950.15 mi (6,357.15 km) |
| Glenn Dale to Onnaing | 3,830.50 mi (6,164.60 km) |
| Glenn Dale to Orange | 4,056.06 mi (6,527.60 km) |
| Glenn Dale to Orchies | 3,813.81 mi (6,137.73 km) |
| Glenn Dale to Orleans | 3,823.24 mi (6,152.90 km) |
| Glenn Dale to Orly | 3,822.15 mi (6,151.15 km) |
| Glenn Dale to Ormesson-sur-Marne | 3,827.22 mi (6,159.32 km) |
| Glenn Dale to Orsay | 3,814.63 mi (6,139.05 km) |
