| Hereford to Olympia Heights (Florida) | 4,321.56 mi (6,954.88 km) |
| Hereford to Omaha (Nebraska) | 4,176.63 mi (6,721.64 km) |
| Hereford to On Top of the World Designated Place (Florida) | 4,232.57 mi (6,811.67 km) |
| Hereford to Onalaska (Wisconsin) | 3,873.13 mi (6,233.20 km) |
| Hereford to Oneida (New York) | 3,310.11 mi (5,327.11 km) |
| Hereford to Oneonta (New York) | 3,312.53 mi (5,331.00 km) |
| Hereford to Ontario (California) | 5,311.94 mi (8,548.73 km) |
| Hereford to Ontario (Oregon) | 4,733.26 mi (7,617.45 km) |
| Hereford to Opa-locka (Florida) | 4,309.11 mi (6,934.84 km) |
| Hereford to Opelika (Alabama) | 4,183.36 mi (6,732.46 km) |
| Hereford to Opelousas (Louisiana) | 4,561.55 mi (7,341.11 km) |
| Hereford to Orange (California) | 5,332.35 mi (8,581.58 km) |
| Hereford to Orange (Texas) | 4,649.28 mi (7,482.29 km) |
| Hereford to Orange City (Florida) | 4,199.49 mi (6,758.42 km) |
| Hereford to Orangeburg (South Carolina) | 3,957.95 mi (6,369.70 km) |
