| Horw to Olympia Heights (Florida) | 4,878.95 mi (7,851.91 km) |
| Horw to Omaha (Nebraska) | 4,780.53 mi (7,693.51 km) |
| Horw to On Top of the World Designated Place (Florida) | 4,804.67 mi (7,732.37 km) |
| Horw to Onalaska (Wisconsin) | 4,476.94 mi (7,204.93 km) |
| Horw to Oneida (New York) | 3,904.08 mi (6,283.00 km) |
| Horw to Oneonta (New York) | 3,904.57 mi (6,283.80 km) |
| Horw to Ontario (California) | 5,909.18 mi (9,509.90 km) |
| Horw to Ontario (Oregon) | 5,319.21 mi (8,560.45 km) |
| Horw to Opa-locka (Florida) | 4,866.80 mi (7,832.35 km) |
| Horw to Opelika (Alabama) | 4,769.76 mi (7,676.18 km) |
| Horw to Opelousas (Louisiana) | 5,154.31 mi (8,295.07 km) |
| Horw to Orange (California) | 5,929.56 mi (9,542.71 km) |
| Horw to Orange (Texas) | 5,243.66 mi (8,438.85 km) |
| Horw to Orange City (Florida) | 4,768.78 mi (7,674.61 km) |
| Horw to Orangeburg (South Carolina) | 4,538.22 mi (7,303.56 km) |
