| Merthyr Tudful to Nottingham | 125.83 mi (202.50 km) |
| Merthyr Tudful to Nuneaton | 97.29 mi (156.57 km) |
| Merthyr Tudful to Oadby | 114.05 mi (183.54 km) |
| Merthyr Tudful to Oakengates | 76.59 mi (123.26 km) |
| Merthyr Tudful to Oakham | 129.01 mi (207.62 km) |
| Merthyr Tudful to Oldbury | 78.17 mi (125.80 km) |
| Merthyr Tudful to Oldham | 135.22 mi (217.62 km) |
| Merthyr Tudful to Ollerton | 141.35 mi (227.48 km) |
| Merthyr Tudful to Olton | 82.21 mi (132.30 km) |
| Merthyr Tudful to Omagh | 254.77 mi (410.02 km) |
| Merthyr Tudful to Ormesby | 214.16 mi (344.66 km) |
| Merthyr Tudful to Ormskirk | 127.66 mi (205.45 km) |
| Merthyr Tudful to Orpington | 151.49 mi (243.79 km) |
| Merthyr Tudful to Ossett | 153.53 mi (247.09 km) |
| Merthyr Tudful to Oswaldtwistle | 144.19 mi (232.06 km) |
