| Severn to Olympia (Washington) | 2,358.17 mi (3,795.10 km) |
| Severn to Olympia Heights (Florida) | 950.45 mi (1,529.60 km) |
| Severn to Omaha (Nebraska) | 1,029.88 mi (1,657.43 km) |
| Severn to On Top of the World Designated Place (Florida) | 762.79 mi (1,227.60 km) |
| Severn to Onalaska (Wisconsin) | 818.02 mi (1,316.48 km) |
| Severn to Oneida (New York) | 277.58 mi (446.72 km) |
| Severn to Oneonta (New York) | 244.66 mi (393.75 km) |
| Severn to Ontario (California) | 2,277.37 mi (3,665.08 km) |
| Severn to Ontario (Oregon) | 2,087.84 mi (3,360.06 km) |
| Severn to Opa-locka (Florida) | 937.50 mi (1,508.75 km) |
| Severn to Opelika (Alabama) | 659.84 mi (1,061.91 km) |
| Severn to Opelousas (Louisiana) | 1,053.74 mi (1,695.83 km) |
| Severn to Orange (California) | 2,294.77 mi (3,693.07 km) |
| Severn to Orange (Texas) | 1,149.83 mi (1,850.47 km) |
| Severn to Orange City (Florida) | 751.96 mi (1,210.16 km) |
