| Boulder to Cookeville (Tennessee) | 1,103.95 mi (1,776.64 km) |
| Boulder to Coolidge (Arizona) | 600.72 mi (966.77 km) |
| Boulder to Coon Rapids (Minnesota) | 702.93 mi (1,131.25 km) |
| Boulder to Cooper City (Florida) | 1,729.30 mi (2,783.03 km) |
| Boulder to Coos Bay (Oregon) | 1,003.79 mi (1,615.44 km) |
| Boulder to Copiague (New York) | 1,669.05 mi (2,686.08 km) |
| Boulder to Coppell (Texas) | 669.16 mi (1,076.92 km) |
| Boulder to Copperas Cove (Texas) | 740.10 mi (1,191.08 km) |
| Boulder to Coral Gables (Florida) | 1,745.35 mi (2,808.87 km) |
| Boulder to Coral Springs (Florida) | 1,720.64 mi (2,769.11 km) |
| Boulder to Coral Terrace (Florida) | 1,741.85 mi (2,803.24 km) |
| Boulder to Coralville (Iowa) | 722.09 mi (1,162.09 km) |
| Boulder to Coram (New York) | 1,686.79 mi (2,714.63 km) |
| Boulder to Corcoran (California) | 823.59 mi (1,325.44 km) |
| Boulder to Cordele (Georgia) | 1,319.51 mi (2,123.55 km) |
