| Rhondda to Oswego (Illinois) | 3,854.15 mi (6,202.65 km) |
| Rhondda to Oswego (New York) | 3,310.44 mi (5,327.63 km) |
| Rhondda to Otsego (Minnesota) | 3,887.79 mi (6,256.79 km) |
| Rhondda to Ottawa (Illinois) | 3,888.10 mi (6,257.30 km) |
| Rhondda to Ottawa (Kansas) | 4,266.15 mi (6,865.70 km) |
| Rhondda to Ottumwa (Iowa) | 4,041.34 mi (6,503.92 km) |
| Rhondda to Overland (Missouri) | 4,072.78 mi (6,554.51 km) |
| Rhondda to Overland Park (Kansas) | 4,230.14 mi (6,807.76 km) |
| Rhondda to Overlea (Maryland) | 3,485.92 mi (5,610.05 km) |
| Rhondda to Oviedo (Florida) | 4,185.02 mi (6,735.14 km) |
| Rhondda to Owasso (Oklahoma) | 4,402.23 mi (7,084.71 km) |
| Rhondda to Owatonna (Minnesota) | 3,927.80 mi (6,321.18 km) |
| Rhondda to Owensboro (Kentucky) | 3,989.04 mi (6,419.73 km) |
| Rhondda to Owings Mills (Maryland) | 3,495.10 mi (5,624.82 km) |
| Rhondda to Owosso (Michigan) | 3,633.76 mi (5,847.97 km) |
