| Duncan to Abilene (Texas) | 178.15 mi (286.71 km) |
| Duncan to Accokeek (Maryland) | 1,192.00 mi (1,918.34 km) |
| Duncan to Acworth (Georgia) | 756.49 mi (1,217.45 km) |
| Duncan to Ada (Oklahoma) | 72.92 mi (117.35 km) |
| Duncan to Addison (Illinois) | 740.77 mi (1,192.16 km) |
| Duncan to Addison (Texas) | 125.84 mi (202.53 km) |
| Duncan to Adelanto (California) | 1,108.84 mi (1,784.51 km) |
| Duncan to Adelphi (Maryland) | 1,197.10 mi (1,926.55 km) |
| Duncan to Adrian (Michigan) | 906.98 mi (1,459.64 km) |
| Duncan to Affton (Missouri) | 504.17 mi (811.38 km) |
| Duncan to Agoura Hills (California) | 1,187.01 mi (1,910.32 km) |
| Duncan to Aguadilla (Puerto Rico) | 2,190.51 mi (3,525.29 km) |
| Duncan to Aiken (South Carolina) | 928.87 mi (1,494.87 km) |
| Duncan to Akron (Ohio) | 1,000.50 mi (1,610.15 km) |
| Duncan to Alabaster (Alabama) | 642.83 mi (1,034.53 km) |
