| Herk-de-Stad to Olympia Heights (Florida) | 4,668.84 mi (7,513.77 km) |
| Herk-de-Stad to Omaha (Nebraska) | 4,502.74 mi (7,246.47 km) |
| Herk-de-Stad to On Top of the World Designated Place (Florida) | 4,579.95 mi (7,370.73 km) |
| Herk-de-Stad to Onalaska (Wisconsin) | 4,200.75 mi (6,760.46 km) |
| Herk-de-Stad to Oneida (New York) | 3,652.67 mi (5,878.41 km) |
| Herk-de-Stad to Oneonta (New York) | 3,656.05 mi (5,883.84 km) |
| Herk-de-Stad to Ontario (California) | 5,614.34 mi (9,035.40 km) |
| Herk-de-Stad to Ontario (Oregon) | 5,018.02 mi (8,075.72 km) |
| Herk-de-Stad to Opa-locka (Florida) | 4,656.40 mi (7,493.75 km) |
| Herk-de-Stad to Opelika (Alabama) | 4,528.57 mi (7,288.03 km) |
| Herk-de-Stad to Opelousas (Louisiana) | 4,904.21 mi (7,892.57 km) |
| Herk-de-Stad to Orange (California) | 5,634.69 mi (9,068.16 km) |
| Herk-de-Stad to Orange (Texas) | 4,991.01 mi (8,032.25 km) |
| Herk-de-Stad to Orange City (Florida) | 4,546.99 mi (7,317.67 km) |
| Herk-de-Stad to Orangeburg (South Carolina) | 4,304.54 mi (6,927.48 km) |
