| Watford to Olympia Heights (Florida) | 4,423.56 mi (7,119.03 km) |
| Watford to Omaha (Nebraska) | 4,275.68 mi (6,881.05 km) |
| Watford to On Top of the World Designated Place (Florida) | 4,335.23 mi (6,976.88 km) |
| Watford to Onalaska (Wisconsin) | 3,972.50 mi (6,393.12 km) |
| Watford to Oneida (New York) | 3,412.54 mi (5,491.95 km) |
| Watford to Oneonta (New York) | 3,415.10 mi (5,496.07 km) |
| Watford to Ontario (California) | 5,405.35 mi (8,699.07 km) |
| Watford to Ontario (Oregon) | 4,821.99 mi (7,760.25 km) |
| Watford to Opa-locka (Florida) | 4,411.12 mi (7,099.01 km) |
| Watford to Opelika (Alabama) | 4,286.12 mi (6,897.85 km) |
| Watford to Opelousas (Louisiana) | 4,664.02 mi (7,506.02 km) |
| Watford to Orange (California) | 5,425.75 mi (8,731.90 km) |
| Watford to Orange (Texas) | 4,751.60 mi (7,646.96 km) |
| Watford to Orange City (Florida) | 4,302.05 mi (6,923.48 km) |
| Watford to Orangeburg (South Carolina) | 4,060.76 mi (6,535.16 km) |
