| Horndean to Olympia Heights (Florida) | 4,406.23 mi (7,091.14 km) |
| Horndean to Omaha (Nebraska) | 4,280.80 mi (6,889.29 km) |
| Horndean to On Top of the World Designated Place (Florida) | 4,321.78 mi (6,955.23 km) |
| Horndean to Onalaska (Wisconsin) | 3,976.97 mi (6,400.31 km) |
| Horndean to Oneida (New York) | 3,407.28 mi (5,483.48 km) |
| Horndean to Oneonta (New York) | 3,408.84 mi (5,485.99 km) |
| Horndean to Ontario (California) | 5,419.39 mi (8,721.67 km) |
| Horndean to Ontario (Oregon) | 4,841.44 mi (7,791.54 km) |
| Horndean to Opa-locka (Florida) | 4,393.86 mi (7,071.23 km) |
| Horndean to Opelika (Alabama) | 4,277.54 mi (6,884.04 km) |
| Horndean to Opelousas (Louisiana) | 4,658.35 mi (7,496.89 km) |
| Horndean to Orange (California) | 5,439.81 mi (8,754.52 km) |
| Horndean to Orange (Texas) | 4,746.79 mi (7,639.22 km) |
| Horndean to Orange City (Florida) | 4,287.78 mi (6,900.51 km) |
| Horndean to Orangeburg (South Carolina) | 4,049.84 mi (6,517.59 km) |
