| Grimes to Olympia Heights (Florida) | 1,342.91 mi (2,161.21 km) |
| Grimes to Omaha (Nebraska) | 120.37 mi (193.72 km) |
| Grimes to On Top of the World Designated Place (Florida) | 1,081.66 mi (1,740.76 km) |
| Grimes to Onalaska (Wisconsin) | 201.32 mi (323.99 km) |
| Grimes to Oneida (New York) | 928.70 mi (1,494.59 km) |
| Grimes to Oneonta (New York) | 960.16 mi (1,545.23 km) |
| Grimes to Ontario (California) | 1,396.27 mi (2,247.07 km) |
| Grimes to Ontario (Oregon) | 1,181.37 mi (1,901.23 km) |
| Grimes to Opa-locka (Florida) | 1,335.32 mi (2,148.99 km) |
| Grimes to Opelika (Alabama) | 775.61 mi (1,248.22 km) |
| Grimes to Opelousas (Louisiana) | 776.44 mi (1,249.56 km) |
| Grimes to Orange (California) | 1,415.02 mi (2,277.25 km) |
| Grimes to Orange (Texas) | 798.40 mi (1,284.89 km) |
| Grimes to Orange City (Florida) | 1,125.47 mi (1,811.28 km) |
| Grimes to Orangeburg (South Carolina) | 904.26 mi (1,455.26 km) |
