| Lake in the Hills to Olympia Heights (Florida) | 1,225.42 mi (1,972.13 km) |
| Lake in the Hills to Omaha (Nebraska) | 402.33 mi (647.48 km) |
| Lake in the Hills to On Top of the World Designated Place (Florida) | 965.36 mi (1,553.60 km) |
| Lake in the Hills to Onalaska (Wisconsin) | 186.00 mi (299.34 km) |
| Lake in the Hills to Oneida (New York) | 647.09 mi (1,041.40 km) |
| Lake in the Hills to Oneonta (New York) | 678.01 mi (1,091.16 km) |
| Lake in the Hills to Ontario (California) | 1,677.38 mi (2,699.48 km) |
| Lake in the Hills to Ontario (Oregon) | 1,442.33 mi (2,321.21 km) |
| Lake in the Hills to Opa-locka (Florida) | 1,215.80 mi (1,956.64 km) |
| Lake in the Hills to Opelika (Alabama) | 678.22 mi (1,091.48 km) |
| Lake in the Hills to Opelousas (Louisiana) | 832.16 mi (1,339.23 km) |
| Lake in the Hills to Orange (California) | 1,695.99 mi (2,729.44 km) |
| Lake in the Hills to Orange (Texas) | 886.35 mi (1,426.44 km) |
| Lake in the Hills to Orange City (Florida) | 997.26 mi (1,604.93 km) |
| Lake in the Hills to Orangeburg (South Carolina) | 725.82 mi (1,168.10 km) |
