| Boulder to Butzbach | 5,020.17 mi (8,079.19 km) |
| Boulder to Buxtehude | 4,909.88 mi (7,901.69 km) |
| Boulder to Cadolzburg | 5,138.15 mi (8,269.05 km) |
| Boulder to Calbe | 5,047.79 mi (8,123.63 km) |
| Boulder to Calw | 5,103.62 mi (8,213.48 km) |
| Boulder to Castrop-Rauxel | 4,925.14 mi (7,926.24 km) |
| Boulder to Celle | 4,961.58 mi (7,984.90 km) |
| Boulder to Cham | 5,206.30 mi (8,378.73 km) |
| Boulder to Chemnitz | 5,134.86 mi (8,263.76 km) |
| Boulder to Clausthal-Zellerfeld | 5,008.34 mi (8,060.14 km) |
| Boulder to Cloppenburg | 4,888.46 mi (7,867.21 km) |
| Boulder to Coburg | 5,101.86 mi (8,210.65 km) |
| Boulder to Coesfeld | 4,901.99 mi (7,888.99 km) |
| Boulder to Cologne | 4,941.56 mi (7,952.67 km) |
| Boulder to Coswig | 5,140.29 mi (8,272.50 km) |
