| South San Francisco to Olympia (Washington) | 649.09 mi (1,044.61 km) |
| South San Francisco to Olympia Heights (Florida) | 2,583.37 mi (4,157.53 km) |
| South San Francisco to Omaha (Nebraska) | 1,422.80 mi (2,289.78 km) |
| South San Francisco to On Top of the World Designated Place (Florida) | 2,370.44 mi (3,814.85 km) |
| South San Francisco to Onalaska (Wisconsin) | 1,678.07 mi (2,700.59 km) |
| South San Francisco to Oneida (New York) | 2,457.61 mi (3,955.14 km) |
| South San Francisco to Oneonta (New York) | 2,493.56 mi (4,012.99 km) |
| South San Francisco to Ontario (California) | 367.37 mi (591.22 km) |
| South San Francisco to Ontario (Oregon) | 523.93 mi (843.19 km) |
| South San Francisco to Opa-locka (Florida) | 2,582.04 mi (4,155.39 km) |
| South San Francisco to Opelika (Alabama) | 2,106.86 mi (3,390.66 km) |
| South San Francisco to Opelousas (Louisiana) | 1,795.66 mi (2,889.83 km) |
| South San Francisco to Orange (California) | 370.39 mi (596.09 km) |
| South San Francisco to Orange (Texas) | 1,716.33 mi (2,762.16 km) |
| South San Francisco to Orange City (Florida) | 2,430.05 mi (3,910.79 km) |
