| Fully to Olympia Heights (Florida) | 4,842.36 mi (7,793.02 km) |
| Fully to Omaha (Nebraska) | 4,774.10 mi (7,683.17 km) |
| Fully to On Top of the World Designated Place (Florida) | 4,773.26 mi (7,681.82 km) |
| Fully to Onalaska (Wisconsin) | 4,469.71 mi (7,193.31 km) |
| Fully to Oneida (New York) | 3,884.34 mi (6,251.25 km) |
| Fully to Oneonta (New York) | 3,883.55 mi (6,249.96 km) |
| Fully to Ontario (California) | 5,915.39 mi (9,519.90 km) |
| Fully to Ontario (Oregon) | 5,333.17 mi (8,582.91 km) |
| Fully to Opa-locka (Florida) | 4,830.31 mi (7,773.64 km) |
| Fully to Opelika (Alabama) | 4,744.83 mi (7,636.06 km) |
| Fully to Opelousas (Louisiana) | 5,132.96 mi (8,260.71 km) |
| Fully to Orange (California) | 5,935.80 mi (9,552.74 km) |
| Fully to Orange (Texas) | 5,223.41 mi (8,406.26 km) |
| Fully to Orange City (Florida) | 4,736.34 mi (7,622.40 km) |
| Fully to Orangeburg (South Carolina) | 4,510.44 mi (7,258.85 km) |
