| Horsforth to Olympia Heights (Florida) | 4,350.08 mi (7,000.78 km) |
| Horsforth to Omaha (Nebraska) | 4,153.16 mi (6,683.86 km) |
| Horsforth to On Top of the World Designated Place (Florida) | 4,252.07 mi (6,843.05 km) |
| Horsforth to Onalaska (Wisconsin) | 3,851.37 mi (6,198.19 km) |
| Horsforth to Oneida (New York) | 3,311.50 mi (5,329.35 km) |
| Horsforth to Oneonta (New York) | 3,316.25 mi (5,336.99 km) |
| Horsforth to Ontario (California) | 5,267.71 mi (8,477.56 km) |
| Horsforth to Ontario (Oregon) | 4,677.23 mi (7,527.28 km) |
| Horsforth to Opa-locka (Florida) | 4,337.47 mi (6,980.49 km) |
| Horsforth to Opelika (Alabama) | 4,191.52 mi (6,745.61 km) |
| Horsforth to Opelousas (Louisiana) | 4,562.61 mi (7,342.80 km) |
| Horsforth to Orange (California) | 5,288.08 mi (8,510.35 km) |
| Horsforth to Orange (Texas) | 4,648.26 mi (7,480.66 km) |
| Horsforth to Orange City (Florida) | 4,220.94 mi (6,792.95 km) |
| Horsforth to Orangeburg (South Carolina) | 3,971.81 mi (6,392.01 km) |
