| Fallbrook to Olympia Heights (Florida) | 2,266.75 mi (3,647.98 km) |
| Fallbrook to Omaha (Nebraska) | 1,280.43 mi (2,060.65 km) |
| Fallbrook to On Top of the World Designated Place (Florida) | 2,075.26 mi (3,339.81 km) |
| Fallbrook to Onalaska (Wisconsin) | 1,571.93 mi (2,529.77 km) |
| Fallbrook to Oneida (New York) | 2,327.48 mi (3,745.71 km) |
| Fallbrook to Oneonta (New York) | 2,356.24 mi (3,792.01 km) |
| Fallbrook to Ontario (California) | 51.20 mi (82.40 km) |
| Fallbrook to Ontario (Oregon) | 736.42 mi (1,185.16 km) |
| Fallbrook to Opa-locka (Florida) | 2,266.99 mi (3,648.36 km) |
| Fallbrook to Opelika (Alabama) | 1,838.64 mi (2,959.01 km) |
| Fallbrook to Opelousas (Louisiana) | 1,483.55 mi (2,387.54 km) |
| Fallbrook to Orange (California) | 45.58 mi (73.36 km) |
| Fallbrook to Orange (Texas) | 1,393.80 mi (2,243.10 km) |
| Fallbrook to Orange City (Florida) | 2,136.37 mi (3,438.16 km) |
| Fallbrook to Orangeburg (South Carolina) | 2,085.56 mi (3,356.39 km) |
