| Niles to Oswego (Illinois) | 36.09 mi (58.08 km) |
| Niles to Oswego (New York) | 581.79 mi (936.30 km) |
| Niles to Otsego (Minnesota) | 366.50 mi (589.83 km) |
| Niles to Ottawa (Illinois) | 70.05 mi (112.73 km) |
| Niles to Ottawa (Kansas) | 458.34 mi (737.63 km) |
| Niles to Ottumwa (Iowa) | 248.34 mi (399.66 km) |
| Niles to Overland (Missouri) | 266.66 mi (429.15 km) |
| Niles to Overland Park (Kansas) | 421.47 mi (678.29 km) |
| Niles to Overlea (Maryland) | 618.97 mi (996.13 km) |
| Niles to Oviedo (Florida) | 995.50 mi (1,602.10 km) |
| Niles to Owasso (Oklahoma) | 584.28 mi (940.31 km) |
| Niles to Owatonna (Minnesota) | 308.50 mi (496.48 km) |
| Niles to Owensboro (Kentucky) | 297.32 mi (478.49 km) |
| Niles to Owings Mills (Maryland) | 604.14 mi (972.28 km) |
| Niles to Owosso (Michigan) | 196.77 mi (316.66 km) |
