| Herndon to Oerlinghausen | 4,014.81 mi (6,461.21 km) |
| Herndon to Oestrich-Winkel | 4,044.41 mi (6,508.85 km) |
| Herndon to Offenburg | 4,086.62 mi (6,576.78 km) |
| Herndon to Oftersheim | 4,086.50 mi (6,576.59 km) |
| Herndon to Ohrdruf | 4,128.75 mi (6,644.58 km) |
| Herndon to Ohringen | 4,128.78 mi (6,644.63 km) |
| Herndon to Olbernhau | 4,235.28 mi (6,816.03 km) |
| Herndon to Olching | 4,233.88 mi (6,813.77 km) |
| Herndon to Oldenburg | 3,964.91 mi (6,380.91 km) |
| Herndon to Oldenburg in Holstein | 4,033.00 mi (6,490.49 km) |
| Herndon to Olfen | 3,971.57 mi (6,391.62 km) |
| Herndon to Olpe | 4,008.77 mi (6,451.49 km) |
| Herndon to Olsberg | 4,025.05 mi (6,477.68 km) |
| Herndon to Oranienburg | 4,166.03 mi (6,704.58 km) |
| Herndon to Ortenberg | 4,076.41 mi (6,560.34 km) |
