| Boulder to Crest Hill (Illinois) | 901.34 mi (1,450.57 km) |
| Boulder to Crestview (Florida) | 1,227.98 mi (1,976.25 km) |
| Boulder to Crestwood (Illinois) | 920.69 mi (1,481.71 km) |
| Boulder to Crestwood (Missouri) | 800.86 mi (1,288.87 km) |
| Boulder to Creve Coeur (Missouri) | 795.97 mi (1,280.99 km) |
| Boulder to Crofton (Maryland) | 1,517.95 mi (2,442.91 km) |
| Boulder to Crossville (Tennessee) | 1,133.86 mi (1,824.76 km) |
| Boulder to Crowley (Louisiana) | 992.38 mi (1,597.08 km) |
| Boulder to Crowley (Texas) | 676.11 mi (1,088.09 km) |
| Boulder to Crown Point (Indiana) | 940.92 mi (1,514.26 km) |
| Boulder to Crystal (Minnesota) | 696.55 mi (1,120.99 km) |
| Boulder to Crystal Lake (Illinois) | 892.01 mi (1,435.55 km) |
| Boulder to Cudahy (California) | 826.15 mi (1,329.56 km) |
| Boulder to Cudahy (Wisconsin) | 920.56 mi (1,481.51 km) |
| Boulder to Cullman (Alabama) | 1,089.49 mi (1,753.36 km) |
