| Norristown to Oerlinghausen | 3,880.76 mi (6,245.48 km) |
| Norristown to Oestrich-Winkel | 3,909.81 mi (6,292.23 km) |
| Norristown to Offenburg | 3,951.76 mi (6,359.75 km) |
| Norristown to Oftersheim | 3,951.81 mi (6,359.83 km) |
| Norristown to Ohrdruf | 3,994.54 mi (6,428.59 km) |
| Norristown to Ohringen | 3,994.12 mi (6,427.91 km) |
| Norristown to Olbernhau | 4,101.26 mi (6,600.35 km) |
| Norristown to Olching | 4,099.14 mi (6,596.93 km) |
| Norristown to Oldenburg | 3,831.22 mi (6,165.75 km) |
| Norristown to Oldenburg in Holstein | 3,900.06 mi (6,276.54 km) |
| Norristown to Olfen | 3,837.34 mi (6,175.60 km) |
| Norristown to Olpe | 3,874.38 mi (6,235.22 km) |
| Norristown to Olsberg | 3,890.80 mi (6,261.64 km) |
| Norristown to Oranienburg | 4,032.71 mi (6,490.03 km) |
| Norristown to Ortenberg | 3,941.95 mi (6,343.95 km) |
