| Duncan to Mauldin (South Carolina) | 886.87 mi (1,427.27 km) |
| Duncan to Maumee (Ohio) | 913.37 mi (1,469.92 km) |
| Duncan to Maumelle (Arkansas) | 314.36 mi (505.91 km) |
| Duncan to Mayagüez (Puerto Rico) | 2,201.10 mi (3,542.33 km) |
| Duncan to Mayfield Heights (Ohio) | 1,015.25 mi (1,633.89 km) |
| Duncan to Mays Chapel (Maryland) | 1,218.30 mi (1,960.67 km) |
| Duncan to Maywood (California) | 1,155.93 mi (1,860.29 km) |
| Duncan to Maywood (Illinois) | 744.96 mi (1,198.90 km) |
| Duncan to McAlester (Oklahoma) | 124.84 mi (200.90 km) |
| Duncan to McAllen (Texas) | 574.88 mi (925.18 km) |
| Duncan to McCalla (Alabama) | 629.96 mi (1,013.82 km) |
| Duncan to McComb (Mississippi) | 488.37 mi (785.95 km) |
| Duncan to McDonough (Georgia) | 791.94 mi (1,274.51 km) |
| Duncan to McFarland (California) | 1,205.24 mi (1,939.64 km) |
| Duncan to McHenry (Illinois) | 748.56 mi (1,204.69 km) |
