| Michigan City to Olympia Heights (Florida) | 1,165.55 mi (1,875.78 km) |
| Michigan City to Omaha (Nebraska) | 476.12 mi (766.25 km) |
| Michigan City to On Top of the World Designated Place (Florida) | 907.86 mi (1,461.06 km) |
| Michigan City to Onalaska (Wisconsin) | 266.49 mi (428.87 km) |
| Michigan City to Oneida (New York) | 579.16 mi (932.07 km) |
| Michigan City to Oneonta (New York) | 606.92 mi (976.75 km) |
| Michigan City to Ontario (California) | 1,747.44 mi (2,812.23 km) |
| Michigan City to Ontario (Oregon) | 1,524.46 mi (2,453.38 km) |
| Michigan City to Opa-locka (Florida) | 1,155.50 mi (1,859.59 km) |
| Michigan City to Opelika (Alabama) | 630.50 mi (1,014.69 km) |
| Michigan City to Opelousas (Louisiana) | 825.26 mi (1,328.13 km) |
| Michigan City to Orange (California) | 1,765.82 mi (2,841.81 km) |
| Michigan City to Orange (Texas) | 887.83 mi (1,428.82 km) |
| Michigan City to Orange City (Florida) | 936.46 mi (1,507.09 km) |
| Michigan City to Orangeburg (South Carolina) | 655.50 mi (1,054.92 km) |
