| Fosses to Olympia Heights (Florida) | 4,582.71 mi (7,375.17 km) |
| Fosses to Omaha (Nebraska) | 4,479.67 mi (7,209.33 km) |
| Fosses to On Top of the World Designated Place (Florida) | 4,504.37 mi (7,249.08 km) |
| Fosses to Onalaska (Wisconsin) | 4,175.63 mi (6,720.03 km) |
| Fosses to Oneida (New York) | 3,599.81 mi (5,793.34 km) |
| Fosses to Oneonta (New York) | 3,600.43 mi (5,794.33 km) |
| Fosses to Ontario (California) | 5,618.85 mi (9,042.66 km) |
| Fosses to Ontario (Oregon) | 5,038.79 mi (8,109.15 km) |
| Fosses to Opa-locka (Florida) | 4,570.47 mi (7,355.46 km) |
| Fosses to Opelika (Alabama) | 4,466.40 mi (7,187.98 km) |
| Fosses to Opelousas (Louisiana) | 4,850.17 mi (7,805.59 km) |
| Fosses to Orange (California) | 5,639.26 mi (9,075.51 km) |
| Fosses to Orange (Texas) | 4,939.40 mi (7,949.20 km) |
| Fosses to Orange City (Florida) | 4,469.19 mi (7,192.46 km) |
| Fosses to Orangeburg (South Carolina) | 4,235.97 mi (6,817.14 km) |
