| Duncan to Cloverleaf (Texas) | 365.58 mi (588.34 km) |
| Duncan to Cloverly (Maryland) | 1,196.34 mi (1,925.33 km) |
| Duncan to Clovis (California) | 1,228.74 mi (1,977.47 km) |
| Duncan to Clovis (New Mexico) | 300.22 mi (483.15 km) |
| Duncan to Clute (Texas) | 408.84 mi (657.96 km) |
| Duncan to Coachella (California) | 1,042.56 mi (1,677.85 km) |
| Duncan to Coalinga (California) | 1,264.66 mi (2,035.28 km) |
| Duncan to Coamo (Puerto Rico) | 2,247.00 mi (3,616.20 km) |
| Duncan to Coatesville (Pennsylvania) | 1,268.36 mi (2,041.22 km) |
| Duncan to Cockeysville (Maryland) | 1,220.00 mi (1,963.39 km) |
| Duncan to Cocoa (Florida) | 1,094.98 mi (1,762.21 km) |
| Duncan to Cocoa Beach (Florida) | 1,104.12 mi (1,776.91 km) |
| Duncan to Coconut Creek (Florida) | 1,198.58 mi (1,928.92 km) |
| Duncan to Coeur d'Alene (Idaho) | 1,332.00 mi (2,143.65 km) |
| Duncan to Cohoes (New York) | 1,418.37 mi (2,282.64 km) |
