| Ridderkerk to Oerlinghausen | 173.43 mi (279.10 km) |
| Ridderkerk to Oestrich-Winkel | 196.31 mi (315.94 km) |
| Ridderkerk to Offenburg | 277.33 mi (446.32 km) |
| Ridderkerk to Oftersheim | 245.41 mi (394.94 km) |
| Ridderkerk to Ohrdruf | 274.13 mi (441.16 km) |
| Ridderkerk to Ohringen | 283.19 mi (455.75 km) |
| Ridderkerk to Olbernhau | 386.29 mi (621.68 km) |
| Ridderkerk to Olching | 390.93 mi (629.14 km) |
| Ridderkerk to Oldenburg | 175.72 mi (282.79 km) |
| Ridderkerk to Oldenburg in Holstein | 310.09 mi (499.04 km) |
| Ridderkerk to Olfen | 119.39 mi (192.14 km) |
| Ridderkerk to Olpe | 151.11 mi (243.19 km) |
| Ridderkerk to Olsberg | 170.39 mi (274.21 km) |
| Ridderkerk to Oranienburg | 369.73 mi (595.02 km) |
| Ridderkerk to Ortenberg | 219.60 mi (353.41 km) |
