| Senec to Olympia Heights (Florida) | 5,247.37 mi (8,444.83 km) |
| Senec to Omaha (Nebraska) | 5,043.43 mi (8,116.61 km) |
| Senec to On Top of the World Designated Place (Florida) | 5,157.57 mi (8,300.30 km) |
| Senec to Onalaska (Wisconsin) | 4,744.63 mi (7,635.75 km) |
| Senec to Oneida (New York) | 4,221.53 mi (6,793.89 km) |
| Senec to Oneonta (New York) | 4,226.49 mi (6,801.89 km) |
| Senec to Ontario (California) | 6,111.65 mi (9,835.75 km) |
| Senec to Ontario (Oregon) | 5,489.04 mi (8,833.75 km) |
| Senec to Opa-locka (Florida) | 5,234.93 mi (8,424.81 km) |
| Senec to Opelika (Alabama) | 5,101.61 mi (8,210.24 km) |
| Senec to Opelousas (Louisiana) | 5,472.35 mi (8,806.89 km) |
| Senec to Orange (California) | 6,131.82 mi (9,868.21 km) |
| Senec to Orange (Texas) | 5,557.41 mi (8,943.79 km) |
| Senec to Orange City (Florida) | 5,125.00 mi (8,247.89 km) |
| Senec to Orangeburg (South Carolina) | 4,880.32 mi (7,854.11 km) |
