| DeKalb to Olympia Heights (Florida) | 1,217.86 mi (1,959.95 km) |
| DeKalb to Omaha (Nebraska) | 380.14 mi (611.77 km) |
| DeKalb to On Top of the World Designated Place (Florida) | 957.02 mi (1,540.17 km) |
| DeKalb to Onalaska (Wisconsin) | 183.75 mi (295.72 km) |
| DeKalb to Oneida (New York) | 670.55 mi (1,079.14 km) |
| DeKalb to Oneonta (New York) | 700.53 mi (1,127.40 km) |
| DeKalb to Ontario (California) | 1,654.08 mi (2,661.98 km) |
| DeKalb to Ontario (Oregon) | 1,427.18 mi (2,296.83 km) |
| DeKalb to Opa-locka (Florida) | 1,208.43 mi (1,944.78 km) |
| DeKalb to Opelika (Alabama) | 666.62 mi (1,072.81 km) |
| DeKalb to Opelousas (Louisiana) | 809.51 mi (1,302.78 km) |
| DeKalb to Orange (California) | 1,672.62 mi (2,691.82 km) |
| DeKalb to Orange (Texas) | 862.22 mi (1,387.61 km) |
| DeKalb to Orange City (Florida) | 990.33 mi (1,593.78 km) |
| DeKalb to Orangeburg (South Carolina) | 724.20 mi (1,165.48 km) |
