| Rock Island to Cadillac (Michigan) | 324.46 mi (522.17 km) |
| Rock Island to Caguas (Puerto Rico) | 2,161.79 mi (3,479.06 km) |
| Rock Island to Cahokia (Illinois) | 201.84 mi (324.83 km) |
| Rock Island to Calabasas (California) | 1,606.45 mi (2,585.32 km) |
| Rock Island to Caldwell (Idaho) | 1,330.09 mi (2,140.58 km) |
| Rock Island to Caledonia (Wisconsin) | 166.30 mi (267.63 km) |
| Rock Island to Calera (Alabama) | 613.74 mi (987.73 km) |
| Rock Island to Calexico (California) | 1,494.41 mi (2,405.02 km) |
| Rock Island to Calhoun (Georgia) | 571.52 mi (919.77 km) |
| Rock Island to California (Maryland) | 777.40 mi (1,251.10 km) |
| Rock Island to California City (California) | 1,535.07 mi (2,470.46 km) |
| Rock Island to Callaway (Florida) | 831.86 mi (1,338.76 km) |
| Rock Island to Calumet City (Illinois) | 157.11 mi (252.85 km) |
| Rock Island to Calverton (Maryland) | 737.04 mi (1,186.15 km) |
| Rock Island to Camano (Washington) | 1,616.90 mi (2,602.15 km) |
