| Cologne to Navodari | 1,101.98 mi (1,773.46 km) |
| Cologne to Negresti-Oas | 768.45 mi (1,236.70 km) |
| Cologne to Nehoiu | 968.31 mi (1,558.34 km) |
| Cologne to Ocna Mures | 830.67 mi (1,336.84 km) |
| Cologne to Odobesti | 986.34 mi (1,587.37 km) |
| Cologne to Odorheiu Secuiesc | 893.86 mi (1,438.53 km) |
| Cologne to Oltenita | 1,028.94 mi (1,655.92 km) |
| Cologne to Onesti | 957.90 mi (1,541.59 km) |
| Cologne to Oradea | 727.47 mi (1,170.75 km) |
| Cologne to Orastie | 821.77 mi (1,322.50 km) |
| Cologne to Oravita | 791.68 mi (1,274.08 km) |
| Cologne to Orsova | 832.60 mi (1,339.95 km) |
| Cologne to Otelu Rosu | 799.44 mi (1,286.58 km) |
| Cologne to Otopeni | 987.85 mi (1,589.79 km) |
| Cologne to Ovidiu | 1,101.64 mi (1,772.91 km) |
