| Duncan to Rockville (Maryland) | 1,187.84 mi (1,911.65 km) |
| Duncan to Rockville Centre (New York) | 1,389.72 mi (2,236.54 km) |
| Duncan to Rockwall (Texas) | 140.93 mi (226.80 km) |
| Duncan to Rocky Mount (North Carolina) | 1,137.31 mi (1,830.32 km) |
| Duncan to Rocky Point (New York) | 1,429.12 mi (2,299.94 km) |
| Duncan to Rocky River (Ohio) | 994.99 mi (1,601.28 km) |
| Duncan to Roessleville (New York) | 1,412.62 mi (2,273.40 km) |
| Duncan to Rogers (Arkansas) | 245.07 mi (394.40 km) |
| Duncan to Rogers (Minnesota) | 770.45 mi (1,239.93 km) |
| Duncan to Rohnert Park (California) | 1,397.50 mi (2,249.06 km) |
| Duncan to Rolla (Missouri) | 416.03 mi (669.54 km) |
| Duncan to Rolling Meadows (Illinois) | 746.58 mi (1,201.50 km) |
| Duncan to Roma (Texas) | 565.02 mi (909.31 km) |
| Duncan to Rome (Georgia) | 725.77 mi (1,168.01 km) |
| Duncan to Rome (New York) | 1,341.61 mi (2,159.11 km) |
