| Boulder to Culpeper (Virginia) | 1,456.45 mi (2,343.93 km) |
| Boulder to Culver City (California) | 834.67 mi (1,343.27 km) |
| Boulder to Cumberland (Maryland) | 1,400.64 mi (2,254.11 km) |
| Boulder to Cupertino (California) | 923.59 mi (1,486.37 km) |
| Boulder to Cutler Bay (Florida) | 1,748.08 mi (2,813.26 km) |
| Boulder to Cutlerville (Michigan) | 1,030.24 mi (1,658.02 km) |
| Boulder to Cuyahoga Falls (Ohio) | 1,243.71 mi (2,001.55 km) |
| Boulder to Cypress (California) | 825.06 mi (1,327.81 km) |
| Boulder to Cypress Gardens (Florida) | 1,577.20 mi (2,538.26 km) |
| Boulder to Cypress Lake (Florida) | 1,631.13 mi (2,625.05 km) |
| Boulder to D'Iberville (Mississippi) | 1,131.43 mi (1,820.86 km) |
| Boulder to Dakota Ridge (Colorado) | 28.72 mi (46.21 km) |
| Boulder to Dale City (Virginia) | 1,488.25 mi (2,395.11 km) |
| Boulder to Dallas (Georgia) | 1,199.81 mi (1,930.91 km) |
| Boulder to Dallas (Oregon) | 978.08 mi (1,574.06 km) |
