| Boulder to Clermont (Florida) | 1,553.30 mi (2,499.80 km) |
| Boulder to Cleveland (Mississippi) | 910.82 mi (1,465.82 km) |
| Boulder to Cleveland (Ohio) | 1,234.04 mi (1,986.00 km) |
| Boulder to Cleveland (Tennessee) | 1,161.79 mi (1,869.71 km) |
| Boulder to Cleveland Heights (Ohio) | 1,239.95 mi (1,995.50 km) |
| Boulder to Cliffside Park (New Jersey) | 1,636.65 mi (2,633.93 km) |
| Boulder to Clifton (Colorado) | 183.03 mi (294.56 km) |
| Boulder to Clifton (New Jersey) | 1,627.47 mi (2,619.16 km) |
| Boulder to Clinton (Iowa) | 792.50 mi (1,275.40 km) |
| Boulder to Clinton (Maryland) | 1,509.87 mi (2,429.90 km) |
| Boulder to Clinton (Mississippi) | 984.03 mi (1,583.64 km) |
| Boulder to Clinton (Utah) | 365.62 mi (588.40 km) |
| Boulder to Clive (Iowa) | 608.43 mi (979.18 km) |
| Boulder to Cloquet (Minnesota) | 788.86 mi (1,269.55 km) |
| Boulder to Cloverleaf (Texas) | 907.77 mi (1,460.92 km) |
