| Rockford to Johnstown (Pennsylvania) | 542.95 mi (873.79 km) |
| Rockford to Joliet (Illinois) | 69.50 mi (111.85 km) |
| Rockford to Jonesboro (Arkansas) | 453.19 mi (729.34 km) |
| Rockford to Joplin (Missouri) | 460.14 mi (740.53 km) |
| Rockford to Joppatowne (Maryland) | 692.13 mi (1,113.88 km) |
| Rockford to Juana Díaz (Puerto Rico) | 2,133.71 mi (3,433.87 km) |
| Rockford to Junction City (Kansas) | 465.05 mi (748.42 km) |
| Rockford to Juneau (Alaska) | 2,223.39 mi (3,578.21 km) |
| Rockford to Jupiter (Florida) | 1,174.14 mi (1,889.59 km) |
| Rockford to Jupiter Farms (Florida) | 1,171.43 mi (1,885.24 km) |
| Rockford to Jurupa Valley (California) | 1,636.63 mi (2,633.90 km) |
| Rockford to Justice (Illinois) | 72.30 mi (116.35 km) |
| Rockford to Kahului (Hawaii) | 4,120.93 mi (6,631.99 km) |
| Rockford to Kailua (Hawaii) | 4,164.38 mi (6,701.93 km) |
| Rockford to Kalamazoo (Michigan) | 177.71 mi (285.99 km) |
