| Gardner to Olympia Heights (Florida) | 1,239.40 mi (1,994.62 km) |
| Gardner to Omaha (Nebraska) | 179.47 mi (288.83 km) |
| Gardner to On Top of the World Designated Place (Florida) | 985.36 mi (1,585.78 km) |
| Gardner to Onalaska (Wisconsin) | 400.19 mi (644.04 km) |
| Gardner to Oneida (New York) | 1,045.04 mi (1,681.83 km) |
| Gardner to Oneonta (New York) | 1,068.66 mi (1,719.85 km) |
| Gardner to Ontario (California) | 1,299.47 mi (2,091.29 km) |
| Gardner to Ontario (Oregon) | 1,193.62 mi (1,920.94 km) |
| Gardner to Opa-locka (Florida) | 1,233.41 mi (1,984.99 km) |
| Gardner to Opelika (Alabama) | 683.07 mi (1,099.30 km) |
| Gardner to Opelousas (Louisiana) | 594.88 mi (957.37 km) |
| Gardner to Orange (California) | 1,316.93 mi (2,119.39 km) |
| Gardner to Orange (Texas) | 604.04 mi (972.11 km) |
| Gardner to Orange City (Florida) | 1,036.09 mi (1,667.43 km) |
| Gardner to Orangeburg (South Carolina) | 864.97 mi (1,392.03 km) |
