| Niles to Olympia Heights (Florida) | 1,204.01 mi (1,937.66 km) |
| Niles to Omaha (Nebraska) | 428.70 mi (689.92 km) |
| Niles to On Top of the World Designated Place (Florida) | 944.69 mi (1,520.33 km) |
| Niles to Onalaska (Wisconsin) | 214.54 mi (345.27 km) |
| Niles to Oneida (New York) | 621.97 mi (1,000.97 km) |
| Niles to Oneonta (New York) | 651.89 mi (1,049.11 km) |
| Niles to Ontario (California) | 1,702.71 mi (2,740.25 km) |
| Niles to Ontario (Oregon) | 1,471.89 mi (2,368.77 km) |
| Niles to Opa-locka (Florida) | 1,194.22 mi (1,921.92 km) |
| Niles to Opelika (Alabama) | 660.74 mi (1,063.36 km) |
| Niles to Opelousas (Louisiana) | 829.30 mi (1,334.63 km) |
| Niles to Orange (California) | 1,721.24 mi (2,770.07 km) |
| Niles to Orange (Texas) | 886.56 mi (1,426.78 km) |
| Niles to Orange City (Florida) | 975.44 mi (1,569.82 km) |
| Niles to Orangeburg (South Carolina) | 700.55 mi (1,127.43 km) |
