| Chicago Heights to Olympia Heights (Florida) | 1,167.55 mi (1,878.99 km) |
| Chicago Heights to Omaha (Nebraska) | 436.56 mi (702.57 km) |
| Chicago Heights to On Top of the World Designated Place (Florida) | 908.04 mi (1,461.35 km) |
| Chicago Heights to Onalaska (Wisconsin) | 244.74 mi (393.87 km) |
| Chicago Heights to Oneida (New York) | 620.83 mi (999.13 km) |
| Chicago Heights to Oneonta (New York) | 648.18 mi (1,043.15 km) |
| Chicago Heights to Ontario (California) | 1,706.41 mi (2,746.21 km) |
| Chicago Heights to Ontario (Oregon) | 1,490.41 mi (2,398.59 km) |
| Chicago Heights to Opa-locka (Florida) | 1,157.81 mi (1,863.32 km) |
| Chicago Heights to Opelika (Alabama) | 623.86 mi (1,004.01 km) |
| Chicago Heights to Opelousas (Louisiana) | 798.32 mi (1,284.77 km) |
| Chicago Heights to Orange (California) | 1,724.75 mi (2,775.71 km) |
| Chicago Heights to Orange (Texas) | 857.80 mi (1,380.49 km) |
| Chicago Heights to Orange City (Florida) | 939.10 mi (1,511.33 km) |
| Chicago Heights to Orangeburg (South Carolina) | 666.16 mi (1,072.08 km) |
