| Hardenberg to Navodari | 1,151.32 mi (1,852.87 km) |
| Hardenberg to Negresti-Oas | 808.39 mi (1,300.98 km) |
| Hardenberg to Nehoiu | 1,018.07 mi (1,638.43 km) |
| Hardenberg to Ocna Mures | 880.78 mi (1,417.48 km) |
| Hardenberg to Odobesti | 1,031.54 mi (1,660.10 km) |
| Hardenberg to Odorheiu Secuiesc | 940.31 mi (1,513.28 km) |
| Hardenberg to Oltenita | 1,084.86 mi (1,745.92 km) |
| Hardenberg to Onesti | 1,000.76 mi (1,610.57 km) |
| Hardenberg to Oradea | 778.53 mi (1,252.93 km) |
| Hardenberg to Orastie | 877.63 mi (1,412.41 km) |
| Hardenberg to Oravita | 857.79 mi (1,380.48 km) |
| Hardenberg to Orsova | 898.12 mi (1,445.39 km) |
| Hardenberg to Otelu Rosu | 860.27 mi (1,384.47 km) |
| Hardenberg to Otopeni | 1,042.90 mi (1,678.39 km) |
| Hardenberg to Ovidiu | 1,151.38 mi (1,852.97 km) |
