| Rockford to Odenton (Maryland) | 684.09 mi (1,100.94 km) |
| Rockford to Odessa (Texas) | 1,022.50 mi (1,645.56 km) |
| Rockford to Ogden (Utah) | 1,179.36 mi (1,898.00 km) |
| Rockford to Oildale (California) | 1,670.48 mi (2,688.38 km) |
| Rockford to Ojus (Florida) | 1,234.49 mi (1,986.73 km) |
| Rockford to Okemos (Michigan) | 238.93 mi (384.52 km) |
| Rockford to Oklahoma City (Oklahoma) | 652.69 mi (1,050.41 km) |
| Rockford to Okmulgee (Oklahoma) | 591.24 mi (951.52 km) |
| Rockford to Olathe (Kansas) | 381.53 mi (614.01 km) |
| Rockford to Old Jamestown (Missouri) | 244.84 mi (394.03 km) |
| Rockford to Oldsmar (Florida) | 1,045.27 mi (1,682.20 km) |
| Rockford to Olean (New York) | 544.23 mi (875.85 km) |
| Rockford to Olive Branch (Mississippi) | 506.05 mi (814.40 km) |
| Rockford to Olivehurst (California) | 1,706.45 mi (2,746.26 km) |
| Rockford to Olney (Maryland) | 663.27 mi (1,067.43 km) |
