| Gary to Oakley (California) | 1,828.16 mi (2,942.14 km) |
| Gary to Oakton (Virginia) | 561.34 mi (903.40 km) |
| Gary to Oakville (Missouri) | 268.08 mi (431.43 km) |
| Gary to Oatfield (Oregon) | 1,771.61 mi (2,851.12 km) |
| Gary to Ocala (Florida) | 905.72 mi (1,457.61 km) |
| Gary to Ocean Acres (New Jersey) | 695.89 mi (1,119.92 km) |
| Gary to Ocean City (New Jersey) | 688.56 mi (1,108.13 km) |
| Gary to Ocean Pines (Maryland) | 681.97 mi (1,097.52 km) |
| Gary to Ocean Pointe (Hawaii) | 4,273.42 mi (6,877.41 km) |
| Gary to Ocean Springs (Mississippi) | 776.76 mi (1,250.08 km) |
| Gary to Oceanside (California) | 1,732.54 mi (2,788.25 km) |
| Gary to Oceanside (New York) | 716.05 mi (1,152.36 km) |
| Gary to Ocoee (Florida) | 956.56 mi (1,539.44 km) |
| Gary to Oconomowoc (Wisconsin) | 119.60 mi (192.48 km) |
| Gary to Odenton (Maryland) | 587.17 mi (944.97 km) |
