| Keystone to Cloverleaf (Texas) | 768.23 mi (1,236.34 km) |
| Keystone to Cloverly (Maryland) | 823.47 mi (1,325.25 km) |
| Keystone to Clovis (California) | 2,228.12 mi (3,585.82 km) |
| Keystone to Clovis (New Mexico) | 1,288.74 mi (2,074.02 km) |
| Keystone to Clute (Texas) | 778.57 mi (1,252.98 km) |
| Keystone to Coachella (California) | 2,016.05 mi (3,244.51 km) |
| Keystone to Coalinga (California) | 2,260.35 mi (3,637.68 km) |
| Keystone to Coamo (Puerto Rico) | 1,241.76 mi (1,998.42 km) |
| Keystone to Coatesville (Pennsylvania) | 905.57 mi (1,457.38 km) |
| Keystone to Cockeysville (Maryland) | 855.25 mi (1,376.40 km) |
| Keystone to Cocoa (Florida) | 112.86 mi (181.63 km) |
| Keystone to Cocoa Beach (Florida) | 120.88 mi (194.53 km) |
| Keystone to Coconut Creek (Florida) | 195.92 mi (315.31 km) |
| Keystone to Coeur d'Alene (Idaho) | 2,273.08 mi (3,658.17 km) |
| Keystone to Cohoes (New York) | 1,127.09 mi (1,813.87 km) |
