| Porthcawl to Olympia Heights (Florida) | 4,285.24 mi (6,896.43 km) |
| Porthcawl to Omaha (Nebraska) | 4,160.69 mi (6,695.98 km) |
| Porthcawl to On Top of the World Designated Place (Florida) | 4,199.51 mi (6,758.46 km) |
| Porthcawl to Onalaska (Wisconsin) | 3,856.58 mi (6,206.57 km) |
| Porthcawl to Oneida (New York) | 3,284.34 mi (5,285.64 km) |
| Porthcawl to Oneonta (New York) | 3,285.84 mi (5,288.05 km) |
| Porthcawl to Ontario (California) | 5,304.81 mi (8,537.27 km) |
| Porthcawl to Ontario (Oregon) | 4,731.94 mi (7,615.33 km) |
| Porthcawl to Opa-locka (Florida) | 4,272.84 mi (6,876.47 km) |
| Porthcawl to Opelika (Alabama) | 4,154.56 mi (6,686.11 km) |
| Porthcawl to Opelousas (Louisiana) | 4,535.38 mi (7,298.98 km) |
| Porthcawl to Orange (California) | 5,325.23 mi (8,570.13 km) |
| Porthcawl to Orange (Texas) | 4,623.88 mi (7,441.42 km) |
| Porthcawl to Orange City (Florida) | 4,165.73 mi (6,704.09 km) |
| Porthcawl to Orangeburg (South Carolina) | 3,927.08 mi (6,320.02 km) |
