| Duncan to Cordele (Georgia) | 836.25 mi (1,345.81 km) |
| Duncan to Corinth (Mississippi) | 534.63 mi (860.40 km) |
| Duncan to Corinth (Texas) | 108.26 mi (174.22 km) |
| Duncan to Cornelius (North Carolina) | 965.31 mi (1,553.51 km) |
| Duncan to Cornelius (Oregon) | 1,521.23 mi (2,448.19 km) |
| Duncan to Corning (New York) | 1,242.49 mi (1,999.59 km) |
| Duncan to Corona (California) | 1,121.74 mi (1,805.26 km) |
| Duncan to Coronado (California) | 1,113.00 mi (1,791.20 km) |
| Duncan to Corpus Christi (Texas) | 472.00 mi (759.61 km) |
| Duncan to Corsicana (Texas) | 189.49 mi (304.96 km) |
| Duncan to Cortland (New York) | 1,294.83 mi (2,083.83 km) |
| Duncan to Corvallis (Oregon) | 1,509.42 mi (2,429.18 km) |
| Duncan to Coshocton (Ohio) | 964.84 mi (1,552.76 km) |
| Duncan to Costa Mesa (California) | 1,143.49 mi (1,840.27 km) |
| Duncan to Coto de Caza (California) | 1,125.61 mi (1,811.50 km) |
