| Merthyr Tudful to Nasaud | 1,275.48 mi (2,052.68 km) |
| Merthyr Tudful to Navodari | 1,549.78 mi (2,494.14 km) |
| Merthyr Tudful to Negresti-Oas | 1,217.33 mi (1,959.11 km) |
| Merthyr Tudful to Nehoiu | 1,416.22 mi (2,279.18 km) |
| Merthyr Tudful to Ocna Mures | 1,278.76 mi (2,057.97 km) |
| Merthyr Tudful to Odobesti | 1,435.09 mi (2,309.56 km) |
| Merthyr Tudful to Odorheiu Secuiesc | 1,342.53 mi (2,160.59 km) |
| Merthyr Tudful to Oltenita | 1,474.40 mi (2,372.82 km) |
| Merthyr Tudful to Onesti | 1,406.85 mi (2,264.11 km) |
| Merthyr Tudful to Oradea | 1,175.57 mi (1,891.90 km) |
| Merthyr Tudful to Orastie | 1,268.01 mi (2,040.67 km) |
| Merthyr Tudful to Oravita | 1,231.95 mi (1,982.63 km) |
| Merthyr Tudful to Orsova | 1,272.99 mi (2,048.68 km) |
| Merthyr Tudful to Otelu Rosu | 1,243.31 mi (2,000.91 km) |
| Merthyr Tudful to Otopeni | 1,433.85 mi (2,307.56 km) |
