| Duncan to River Ridge (Louisiana) | 549.91 mi (884.99 km) |
| Duncan to Riverbank (California) | 1,299.98 mi (2,092.12 km) |
| Duncan to Riverdale (Georgia) | 775.81 mi (1,248.55 km) |
| Duncan to Riverdale (Illinois) | 743.10 mi (1,195.90 km) |
| Duncan to Riverside (California) | 1,111.36 mi (1,788.56 km) |
| Duncan to Riverside (Ohio) | 840.51 mi (1,352.67 km) |
| Duncan to Riverton (Utah) | 871.75 mi (1,402.95 km) |
| Duncan to Riverton (Wyoming) | 813.79 mi (1,309.67 km) |
| Duncan to Riverview (Florida) | 1,031.70 mi (1,660.37 km) |
| Duncan to Riverview (Michigan) | 954.27 mi (1,535.74 km) |
| Duncan to Riviera Beach (Florida) | 1,186.04 mi (1,908.74 km) |
| Duncan to Riviera Beach (Maryland) | 1,222.03 mi (1,966.66 km) |
| Duncan to Roanoke (Virginia) | 1,021.26 mi (1,643.56 km) |
| Duncan to Roanoke Rapids (North Carolina) | 1,145.85 mi (1,844.07 km) |
| Duncan to Robbinsdale (Minnesota) | 763.99 mi (1,229.52 km) |
