| Duncan to Firestone (Colorado) | 546.96 mi (880.24 km) |
| Duncan to Fish Hawk (Florida) | 1,035.23 mi (1,666.04 km) |
| Duncan to Fishers (Indiana) | 755.67 mi (1,216.13 km) |
| Duncan to Fitchburg (Massachusetts) | 1,508.44 mi (2,427.59 km) |
| Duncan to Fitchburg (Wisconsin) | 740.75 mi (1,192.13 km) |
| Duncan to Five Corners (Washington) | 1,504.09 mi (2,420.61 km) |
| Duncan to Five Forks (South Carolina) | 891.08 mi (1,434.05 km) |
| Duncan to Flagstaff (Arizona) | 777.23 mi (1,250.83 km) |
| Duncan to Flat Rock (Michigan) | 948.38 mi (1,526.27 km) |
| Duncan to Fleming Island (Florida) | 993.60 mi (1,599.04 km) |
| Duncan to Flint (Michigan) | 962.57 mi (1,549.11 km) |
| Duncan to Floral Park (New York) | 1,387.09 mi (2,232.31 km) |
| Duncan to Florence (Alabama) | 582.78 mi (937.89 km) |
| Duncan to Florence (Arizona) | 781.21 mi (1,257.23 km) |
| Duncan to Florence (Kentucky) | 795.45 mi (1,280.16 km) |
