| Roman to Olympia Heights (Florida) | 5,684.55 mi (9,148.40 km) |
| Roman to Omaha (Nebraska) | 5,411.82 mi (8,709.48 km) |
| Roman to On Top of the World Designated Place (Florida) | 5,586.44 mi (8,990.51 km) |
| Roman to Onalaska (Wisconsin) | 5,118.24 mi (8,237.01 km) |
| Roman to Oneida (New York) | 4,631.60 mi (7,453.84 km) |
| Roman to Oneonta (New York) | 4,639.34 mi (7,466.29 km) |
| Roman to Ontario (California) | 6,424.28 mi (10,338.88 km) |
| Roman to Ontario (Oregon) | 5,778.34 mi (9,299.33 km) |
| Roman to Opa-locka (Florida) | 5,671.99 mi (9,128.18 km) |
| Roman to Opelika (Alabama) | 5,517.92 mi (8,880.23 km) |
| Roman to Opelousas (Louisiana) | 5,878.51 mi (9,460.55 km) |
| Roman to Orange (California) | 6,444.11 mi (10,370.80 km) |
| Roman to Orange (Texas) | 5,960.37 mi (9,592.29 km) |
| Roman to Orange City (Florida) | 5,555.82 mi (8,941.22 km) |
| Roman to Orangeburg (South Carolina) | 5,303.49 mi (8,535.14 km) |
