| Duncan to Rancho Cordova (California) | 1,320.69 mi (2,125.45 km) |
| Duncan to Rancho Cucamonga (California) | 1,119.47 mi (1,801.62 km) |
| Duncan to Rancho Mirage (California) | 1,058.00 mi (1,702.69 km) |
| Duncan to Rancho Palos Verdes (California) | 1,168.16 mi (1,879.96 km) |
| Duncan to Rancho San Diego (California) | 1,097.92 mi (1,766.94 km) |
| Duncan to Rancho Santa Margarita (California) | 1,125.96 mi (1,812.06 km) |
| Duncan to Randallstown (Maryland) | 1,209.66 mi (1,946.76 km) |
| Duncan to Rantoul (Illinois) | 666.93 mi (1,073.32 km) |
| Duncan to Rapid City (South Dakota) | 716.46 mi (1,153.03 km) |
| Duncan to Ravenna (Ohio) | 1,016.11 mi (1,635.27 km) |
| Duncan to Raymondville (Texas) | 557.30 mi (896.88 km) |
| Duncan to Raymore (Missouri) | 351.43 mi (565.58 km) |
| Duncan to Raytown (Missouri) | 362.29 mi (583.05 km) |
| Duncan to Reading (Ohio) | 811.55 mi (1,306.07 km) |
| Duncan to Reading (Pennsylvania) | 1,267.43 mi (2,039.73 km) |
