| Merthyr Tudful to Opole | 922.24 mi (1,484.20 km) |
| Merthyr Tudful to Orzesze | 965.77 mi (1,554.25 km) |
| Merthyr Tudful to Osowa | 921.52 mi (1,483.04 km) |
| Merthyr Tudful to Ostroda | 981.72 mi (1,579.92 km) |
| Merthyr Tudful to Ostroleka | 1,050.08 mi (1,689.95 km) |
| Merthyr Tudful to Ostrow Mazowiecka | 1,065.70 mi (1,715.09 km) |
| Merthyr Tudful to Ostrow Wielkopolski | 904.50 mi (1,455.65 km) |
| Merthyr Tudful to Ostrowiec Swietokrzyski | 1,065.83 mi (1,715.29 km) |
| Merthyr Tudful to Ostrzeszow | 912.05 mi (1,467.80 km) |
| Merthyr Tudful to Oswiecim | 987.96 mi (1,589.97 km) |
| Merthyr Tudful to Otwock | 1,045.24 mi (1,682.16 km) |
| Merthyr Tudful to Ozarow Mazowiecki | 1,024.69 mi (1,649.08 km) |
| Merthyr Tudful to Ozimek | 934.08 mi (1,503.26 km) |
| Merthyr Tudful to Ozorkow | 963.29 mi (1,550.27 km) |
| Merthyr Tudful to Pabianice | 970.83 mi (1,562.40 km) |
