| Rhondda to Odessa (Texas) | 4,877.94 mi (7,850.29 km) |
| Rhondda to Ogden (Utah) | 4,726.35 mi (7,606.32 km) |
| Rhondda to Oildale (California) | 5,276.51 mi (8,491.73 km) |
| Rhondda to Ojus (Florida) | 4,276.42 mi (6,882.23 km) |
| Rhondda to Okemos (Michigan) | 3,655.80 mi (5,883.44 km) |
| Rhondda to Oklahoma City (Oklahoma) | 4,508.12 mi (7,255.12 km) |
| Rhondda to Okmulgee (Oklahoma) | 4,442.74 mi (7,149.89 km) |
| Rhondda to Olathe (Kansas) | 4,235.39 mi (6,816.20 km) |
| Rhondda to Old Jamestown (Missouri) | 4,062.70 mi (6,538.28 km) |
| Rhondda to Oldsmar (Florida) | 4,277.80 mi (6,884.45 km) |
| Rhondda to Olean (New York) | 3,445.79 mi (5,545.46 km) |
| Rhondda to Olive Branch (Mississippi) | 4,232.54 mi (6,811.61 km) |
| Rhondda to Olivehurst (California) | 5,149.15 mi (8,286.76 km) |
| Rhondda to Olney (Maryland) | 3,518.33 mi (5,662.20 km) |
| Rhondda to Olympia (Washington) | 4,737.38 mi (7,624.08 km) |
