| River Forest to Oskaloosa (Iowa) | 252.54 mi (406.42 km) |
| River Forest to Oswego (Illinois) | 30.42 mi (48.95 km) |
| River Forest to Oswego (New York) | 584.48 mi (940.63 km) |
| River Forest to Otsego (Minnesota) | 372.05 mi (598.75 km) |
| River Forest to Ottawa (Illinois) | 63.97 mi (102.96 km) |
| River Forest to Ottawa (Kansas) | 453.58 mi (729.97 km) |
| River Forest to Ottumwa (Iowa) | 245.68 mi (395.39 km) |
| River Forest to Overland (Missouri) | 258.59 mi (416.17 km) |
| River Forest to Overland Park (Kansas) | 416.71 mi (670.63 km) |
| River Forest to Overlea (Maryland) | 617.36 mi (993.54 km) |
| River Forest to Oviedo (Florida) | 987.32 mi (1,588.94 km) |
| River Forest to Owasso (Oklahoma) | 578.03 mi (930.26 km) |
| River Forest to Owatonna (Minnesota) | 312.68 mi (503.21 km) |
| River Forest to Owensboro (Kentucky) | 288.29 mi (463.96 km) |
| River Forest to Owings Mills (Maryland) | 602.51 mi (969.64 km) |
