| Heerlen to Navodari | 1,141.75 mi (1,837.47 km) |
| Heerlen to Negresti-Oas | 809.62 mi (1,302.96 km) |
| Heerlen to Nehoiu | 1,008.12 mi (1,622.42 km) |
| Heerlen to Ocna Mures | 870.58 mi (1,401.06 km) |
| Heerlen to Odobesti | 1,026.75 mi (1,652.40 km) |
| Heerlen to Odorheiu Secuiesc | 934.19 mi (1,503.43 km) |
| Heerlen to Oltenita | 1,067.72 mi (1,718.33 km) |
| Heerlen to Onesti | 998.61 mi (1,607.10 km) |
| Heerlen to Oradea | 767.37 mi (1,234.97 km) |
| Heerlen to Orastie | 860.79 mi (1,385.30 km) |
| Heerlen to Oravita | 828.73 mi (1,333.70 km) |
| Heerlen to Orsova | 869.72 mi (1,399.67 km) |
| Heerlen to Otelu Rosu | 837.59 mi (1,347.97 km) |
| Heerlen to Otopeni | 1,026.82 mi (1,652.51 km) |
| Heerlen to Ovidiu | 1,141.35 mi (1,836.82 km) |
