| Cahokia to Olympia Heights (Florida) | 1,056.09 mi (1,699.61 km) |
| Cahokia to Omaha (Nebraska) | 362.69 mi (583.69 km) |
| Cahokia to On Top of the World Designated Place (Florida) | 794.44 mi (1,278.53 km) |
| Cahokia to Onalaska (Wisconsin) | 371.66 mi (598.12 km) |
| Cahokia to Oneida (New York) | 819.18 mi (1,318.35 km) |
| Cahokia to Oneonta (New York) | 836.77 mi (1,346.65 km) |
| Cahokia to Ontario (California) | 1,552.80 mi (2,498.99 km) |
| Cahokia to Ontario (Oregon) | 1,434.23 mi (2,308.16 km) |
| Cahokia to Opa-locka (Florida) | 1,048.31 mi (1,687.09 km) |
| Cahokia to Opelika (Alabama) | 488.86 mi (786.74 km) |
| Cahokia to Opelousas (Louisiana) | 565.91 mi (910.74 km) |
| Cahokia to Orange (California) | 1,569.93 mi (2,526.57 km) |
| Cahokia to Orange (Texas) | 617.91 mi (994.43 km) |
| Cahokia to Orange City (Florida) | 837.88 mi (1,348.43 km) |
| Cahokia to Orangeburg (South Carolina) | 626.82 mi (1,008.77 km) |
