| Llantrisant to Oswego (Illinois) | 3,858.02 mi (6,208.89 km) |
| Llantrisant to Oswego (New York) | 3,313.95 mi (5,333.28 km) |
| Llantrisant to Otsego (Minnesota) | 3,892.06 mi (6,263.66 km) |
| Llantrisant to Ottawa (Illinois) | 3,891.98 mi (6,263.53 km) |
| Llantrisant to Ottawa (Kansas) | 4,270.13 mi (6,872.11 km) |
| Llantrisant to Ottumwa (Iowa) | 4,045.34 mi (6,510.35 km) |
| Llantrisant to Overland (Missouri) | 4,076.57 mi (6,560.60 km) |
| Llantrisant to Overland Park (Kansas) | 4,234.11 mi (6,814.15 km) |
| Llantrisant to Overlea (Maryland) | 3,489.12 mi (5,615.19 km) |
| Llantrisant to Oviedo (Florida) | 4,187.71 mi (6,739.47 km) |
| Llantrisant to Owasso (Oklahoma) | 4,406.12 mi (7,090.96 km) |
| Llantrisant to Owatonna (Minnesota) | 3,931.99 mi (6,327.92 km) |
| Llantrisant to Owensboro (Kentucky) | 3,992.62 mi (6,425.50 km) |
| Llantrisant to Owings Mills (Maryland) | 3,498.31 mi (5,629.99 km) |
| Llantrisant to Owosso (Michigan) | 3,637.55 mi (5,854.08 km) |
