| Glenn Dale to Oerlinghausen | 3,991.48 mi (6,423.67 km) |
| Glenn Dale to Oestrich-Winkel | 4,020.26 mi (6,469.98 km) |
| Glenn Dale to Offenburg | 4,061.90 mi (6,537.00 km) |
| Glenn Dale to Oftersheim | 4,062.18 mi (6,537.45 km) |
| Glenn Dale to Ohrdruf | 4,105.21 mi (6,606.69 km) |
| Glenn Dale to Ohringen | 4,104.50 mi (6,605.56 km) |
| Glenn Dale to Olbernhau | 4,211.99 mi (6,778.55 km) |
| Glenn Dale to Olching | 4,209.46 mi (6,774.47 km) |
| Glenn Dale to Oldenburg | 3,942.01 mi (6,344.05 km) |
| Glenn Dale to Oldenburg in Holstein | 4,010.86 mi (6,454.85 km) |
| Glenn Dale to Olfen | 3,948.00 mi (6,353.69 km) |
| Glenn Dale to Olpe | 3,984.98 mi (6,413.20 km) |
| Glenn Dale to Olsberg | 4,001.46 mi (6,439.72 km) |
| Glenn Dale to Oranienburg | 4,143.53 mi (6,668.36 km) |
| Glenn Dale to Ortenberg | 4,052.50 mi (6,521.87 km) |
