| Rockwall to Olympia (Washington) | 1,693.88 mi (2,726.03 km) |
| Rockwall to Olympia Heights (Florida) | 1,087.95 mi (1,750.88 km) |
| Rockwall to Omaha (Nebraska) | 577.03 mi (928.63 km) |
| Rockwall to On Top of the World Designated Place (Florida) | 877.52 mi (1,412.24 km) |
| Rockwall to Onalaska (Wisconsin) | 808.76 mi (1,301.58 km) |
| Rockwall to Oneida (New York) | 1,325.70 mi (2,133.51 km) |
| Rockwall to Oneonta (New York) | 1,336.03 mi (2,150.14 km) |
| Rockwall to Ontario (California) | 1,220.27 mi (1,963.84 km) |
| Rockwall to Ontario (Oregon) | 1,344.30 mi (2,163.45 km) |
| Rockwall to Opa-locka (Florida) | 1,086.24 mi (1,748.14 km) |
| Rockwall to Opelika (Alabama) | 642.39 mi (1,033.83 km) |
| Rockwall to Opelousas (Louisiana) | 304.65 mi (490.29 km) |
| Rockwall to Orange (California) | 1,233.37 mi (1,984.92 km) |
| Rockwall to Orange (Texas) | 249.24 mi (401.11 km) |
| Rockwall to Orange City (Florida) | 938.09 mi (1,509.71 km) |
