| Boulder to Caño Martin Peña (Puerto Rico) | 2,762.14 mi (4,445.24 km) |
| Boulder to Cañon City (Colorado) | 109.31 mi (175.91 km) |
| Boulder to Canóvanas (Puerto Rico) | 2,772.34 mi (4,461.65 km) |
| Boulder to Canton (Georgia) | 1,207.90 mi (1,943.94 km) |
| Boulder to Canton (Illinois) | 801.51 mi (1,289.91 km) |
| Boulder to Canton (Mississippi) | 988.62 mi (1,591.03 km) |
| Boulder to Canton (Ohio) | 1,253.72 mi (2,017.67 km) |
| Boulder to Canyon (Texas) | 392.78 mi (632.12 km) |
| Boulder to Canyon Lake (California) | 794.17 mi (1,278.09 km) |
| Boulder to Canyon Lake (Texas) | 804.60 mi (1,294.88 km) |
| Boulder to Cape Coral (Florida) | 1,621.91 mi (2,610.21 km) |
| Boulder to Cape Girardeau (Missouri) | 865.85 mi (1,393.45 km) |
| Boulder to Carbondale (Illinois) | 875.50 mi (1,408.98 km) |
| Boulder to Carlisle (Pennsylvania) | 1,475.97 mi (2,375.35 km) |
| Boulder to Carlsbad (California) | 819.11 mi (1,318.22 km) |
