| Keller to Olympia Heights (Florida) | 1,130.66 mi (1,819.61 km) |
| Keller to Omaha (Nebraska) | 579.09 mi (931.96 km) |
| Keller to On Top of the World Designated Place (Florida) | 922.29 mi (1,484.29 km) |
| Keller to Onalaska (Wisconsin) | 823.46 mi (1,325.23 km) |
| Keller to Oneida (New York) | 1,361.23 mi (2,190.68 km) |
| Keller to Oneonta (New York) | 1,372.65 mi (2,209.06 km) |
| Keller to Ontario (California) | 1,174.99 mi (1,890.96 km) |
| Keller to Ontario (Oregon) | 1,309.13 mi (2,106.84 km) |
| Keller to Opa-locka (Florida) | 1,129.15 mi (1,817.19 km) |
| Keller to Opelika (Alabama) | 688.06 mi (1,107.32 km) |
| Keller to Opelousas (Louisiana) | 345.00 mi (555.22 km) |
| Keller to Orange (California) | 1,188.01 mi (1,911.92 km) |
| Keller to Orange (Texas) | 281.67 mi (453.31 km) |
| Keller to Orange City (Florida) | 982.96 mi (1,581.92 km) |
| Keller to Orangeburg (South Carolina) | 945.43 mi (1,521.53 km) |
