| Grand Forks to Olympia Heights (Florida) | 1,783.02 mi (2,869.49 km) |
| Grand Forks to Omaha (Nebraska) | 462.87 mi (744.92 km) |
| Grand Forks to On Top of the World Designated Place (Florida) | 1,520.61 mi (2,447.19 km) |
| Grand Forks to Onalaska (Wisconsin) | 396.76 mi (638.53 km) |
| Grand Forks to Oneida (New York) | 1,086.14 mi (1,747.98 km) |
| Grand Forks to Oneonta (New York) | 1,132.22 mi (1,822.14 km) |
| Grand Forks to Ontario (California) | 1,428.90 mi (2,299.59 km) |
| Grand Forks to Ontario (Oregon) | 989.04 mi (1,591.71 km) |
| Grand Forks to Opa-locka (Florida) | 1,774.47 mi (2,855.74 km) |
| Grand Forks to Opelika (Alabama) | 1,218.60 mi (1,961.14 km) |
| Grand Forks to Opelousas (Louisiana) | 1,230.79 mi (1,980.77 km) |
| Grand Forks to Orange (California) | 1,449.26 mi (2,332.37 km) |
| Grand Forks to Orange (Texas) | 1,242.37 mi (1,999.41 km) |
| Grand Forks to Orange City (Florida) | 1,559.19 mi (2,509.28 km) |
| Grand Forks to Orangeburg (South Carolina) | 1,304.34 mi (2,099.13 km) |
