| Helena to Cloverleaf (Texas) | 1,471.79 mi (2,368.62 km) |
| Helena to Cloverly (Maryland) | 1,831.02 mi (2,946.74 km) |
| Helena to Clovis (California) | 781.27 mi (1,257.33 km) |
| Helena to Clovis (New Mexico) | 958.13 mi (1,541.96 km) |
| Helena to Clute (Texas) | 1,508.91 mi (2,428.35 km) |
| Helena to Coachella (California) | 917.57 mi (1,476.69 km) |
| Helena to Coalinga (California) | 839.83 mi (1,351.57 km) |
| Helena to Coamo (Puerto Rico) | 3,247.34 mi (5,226.10 km) |
| Helena to Coatesville (Pennsylvania) | 1,859.33 mi (2,992.31 km) |
| Helena to Cockeysville (Maryland) | 1,836.61 mi (2,955.74 km) |
| Helena to Cocoa (Florida) | 2,103.15 mi (3,384.69 km) |
| Helena to Cocoa Beach (Florida) | 2,111.56 mi (3,398.23 km) |
| Helena to Coconut Creek (Florida) | 2,232.88 mi (3,593.47 km) |
| Helena to Coeur d'Alene (Idaho) | 236.94 mi (381.32 km) |
| Helena to Cohoes (New York) | 1,881.64 mi (3,028.21 km) |
