| Castricum to Navodari | 1,228.19 mi (1,976.58 km) |
| Castricum to Negresti-Oas | 887.05 mi (1,427.57 km) |
| Castricum to Nehoiu | 1,094.71 mi (1,761.77 km) |
| Castricum to Ocna Mures | 957.15 mi (1,540.39 km) |
| Castricum to Odobesti | 1,109.33 mi (1,785.29 km) |
| Castricum to Odorheiu Secuiesc | 1,017.70 mi (1,637.83 km) |
| Castricum to Oltenita | 1,159.77 mi (1,866.47 km) |
| Castricum to Onesti | 1,079.05 mi (1,736.56 km) |
| Castricum to Oradea | 854.48 mi (1,375.15 km) |
| Castricum to Orastie | 952.31 mi (1,532.59 km) |
| Castricum to Oravita | 928.72 mi (1,494.63 km) |
| Castricum to Orsova | 969.36 mi (1,560.03 km) |
| Castricum to Otelu Rosu | 933.24 mi (1,501.91 km) |
| Castricum to Otopeni | 1,118.04 mi (1,799.31 km) |
| Castricum to Ovidiu | 1,228.14 mi (1,976.51 km) |
