| Boulder to Cehegin | 5,191.31 mi (8,354.60 km) |
| Boulder to Cervello | 5,196.44 mi (8,362.85 km) |
| Boulder to Cervera | 5,157.31 mi (8,299.88 km) |
| Boulder to Ceuti | 5,213.94 mi (8,391.02 km) |
| Boulder to Cheste | 5,176.21 mi (8,330.31 km) |
| Boulder to Chiclana de la Frontera | 5,077.17 mi (8,170.92 km) |
| Boulder to Chipiona | 5,051.34 mi (8,129.34 km) |
| Boulder to Chiva | 5,175.13 mi (8,328.57 km) |
| Boulder to Churriana de la Vega | 5,154.07 mi (8,294.67 km) |
| Boulder to Ciempozuelos | 5,025.73 mi (8,088.13 km) |
| Boulder to Cieza | 5,200.73 mi (8,369.76 km) |
| Boulder to Cisterniga | 4,920.07 mi (7,918.08 km) |
| Boulder to Ciudad de Melilla | 5,266.06 mi (8,474.90 km) |
| Boulder to Ciudad Real | 5,063.63 mi (8,149.12 km) |
| Boulder to Ciudad-Rodrigo | 4,885.31 mi (7,862.15 km) |
