| Rock Island to Castle Pines (Colorado) | 762.82 mi (1,227.64 km) |
| Rock Island to Castle Rock (Colorado) | 763.51 mi (1,228.75 km) |
| Rock Island to Castro Valley (California) | 1,686.67 mi (2,714.44 km) |
| Rock Island to Catalina Foothills (Arizona) | 1,283.60 mi (2,065.75 km) |
| Rock Island to Cataño (Puerto Rico) | 2,146.28 mi (3,454.11 km) |
| Rock Island to Cathedral City (California) | 1,503.84 mi (2,420.19 km) |
| Rock Island to Catonsville (Maryland) | 743.49 mi (1,196.52 km) |
| Rock Island to Cave Spring (Virginia) | 635.99 mi (1,023.53 km) |
| Rock Island to Cayce (South Carolina) | 735.43 mi (1,183.56 km) |
| Rock Island to Cayey (Puerto Rico) | 2,163.39 mi (3,481.64 km) |
| Rock Island to Cedar City (Utah) | 1,223.41 mi (1,968.88 km) |
| Rock Island to Cedar Falls (Iowa) | 120.37 mi (193.71 km) |
| Rock Island to Cedar Hill (Texas) | 707.24 mi (1,138.20 km) |
| Rock Island to Cedar Lake (Indiana) | 163.02 mi (262.36 km) |
| Rock Island to Cedar Mill (Oregon) | 1,627.57 mi (2,619.33 km) |
