| Festus to Olympia Heights (Florida) | 1,044.29 mi (1,680.63 km) |
| Festus to Omaha (Nebraska) | 366.07 mi (589.14 km) |
| Festus to On Top of the World Designated Place (Florida) | 783.29 mi (1,260.58 km) |
| Festus to Onalaska (Wisconsin) | 393.88 mi (633.88 km) |
| Festus to Oneida (New York) | 841.30 mi (1,353.93 km) |
| Festus to Oneonta (New York) | 857.92 mi (1,380.70 km) |
| Festus to Ontario (California) | 1,539.17 mi (2,477.06 km) |
| Festus to Ontario (Oregon) | 1,432.68 mi (2,305.67 km) |
| Festus to Opa-locka (Florida) | 1,036.77 mi (1,668.52 km) |
| Festus to Opelika (Alabama) | 477.04 mi (767.72 km) |
| Festus to Opelousas (Louisiana) | 540.07 mi (869.16 km) |
| Festus to Orange (California) | 1,556.14 mi (2,504.36 km) |
| Festus to Orange (Texas) | 591.20 mi (951.44 km) |
| Festus to Orange City (Florida) | 828.04 mi (1,332.61 km) |
| Festus to Orangeburg (South Carolina) | 625.76 mi (1,007.06 km) |
