| Middelharnis to Olympia Heights (Florida) | 4,614.20 mi (7,425.84 km) |
| Middelharnis to Omaha (Nebraska) | 4,435.34 mi (7,137.99 km) |
| Middelharnis to On Top of the World Designated Place (Florida) | 4,522.41 mi (7,278.12 km) |
| Middelharnis to Onalaska (Wisconsin) | 4,133.66 mi (6,652.48 km) |
| Middelharnis to Oneida (New York) | 3,590.22 mi (5,777.91 km) |
| Middelharnis to Oneonta (New York) | 3,594.15 mi (5,784.23 km) |
| Middelharnis to Ontario (California) | 5,544.40 mi (8,922.85 km) |
| Middelharnis to Ontario (Oregon) | 4,947.52 mi (7,962.26 km) |
| Middelharnis to Opa-locka (Florida) | 4,601.71 mi (7,405.73 km) |
| Middelharnis to Opelika (Alabama) | 4,467.81 mi (7,190.25 km) |
| Middelharnis to Opelousas (Louisiana) | 4,841.66 mi (7,791.89 km) |
| Middelharnis to Orange (California) | 5,564.75 mi (8,955.60 km) |
| Middelharnis to Orange (Texas) | 4,927.96 mi (7,930.78 km) |
| Middelharnis to Orange City (Florida) | 4,490.04 mi (7,226.02 km) |
| Middelharnis to Orangeburg (South Carolina) | 4,245.32 mi (6,832.18 km) |
