| Oak Forest to Olympia Heights (Florida) | 1,176.02 mi (1,892.63 km) |
| Oak Forest to Omaha (Nebraska) | 430.44 mi (692.72 km) |
| Oak Forest to On Top of the World Designated Place (Florida) | 916.39 mi (1,474.79 km) |
| Oak Forest to Onalaska (Wisconsin) | 235.77 mi (379.44 km) |
| Oak Forest to Oneida (New York) | 625.21 mi (1,006.17 km) |
| Oak Forest to Oneonta (New York) | 653.10 mi (1,051.06 km) |
| Oak Forest to Ontario (California) | 1,701.27 mi (2,737.93 km) |
| Oak Forest to Ontario (Oregon) | 1,482.68 mi (2,386.15 km) |
| Oak Forest to Opa-locka (Florida) | 1,166.31 mi (1,876.99 km) |
| Oak Forest to Opelika (Alabama) | 631.61 mi (1,016.48 km) |
| Oak Forest to Opelousas (Louisiana) | 802.54 mi (1,291.56 km) |
| Oak Forest to Orange (California) | 1,719.65 mi (2,767.50 km) |
| Oak Forest to Orange (Texas) | 861.17 mi (1,385.93 km) |
| Oak Forest to Orange City (Florida) | 947.63 mi (1,525.06 km) |
| Oak Forest to Orangeburg (South Carolina) | 675.08 mi (1,086.44 km) |
