| Duncan to Red Bank (New Jersey) | 1,363.83 mi (2,194.87 km) |
| Duncan to Red Bank (Tennessee) | 716.68 mi (1,153.39 km) |
| Duncan to Red Bluff (California) | 1,386.18 mi (2,230.85 km) |
| Duncan to Red Hill (South Carolina) | 1,080.88 mi (1,739.51 km) |
| Duncan to Red Oak (Texas) | 154.09 mi (247.98 km) |
| Duncan to Red Wing (Minnesota) | 748.93 mi (1,205.28 km) |
| Duncan to Redan (Georgia) | 788.05 mi (1,268.25 km) |
| Duncan to Redding (California) | 1,396.91 mi (2,248.11 km) |
| Duncan to Redland (Maryland) | 1,188.86 mi (1,913.28 km) |
| Duncan to Redlands (California) | 1,097.64 mi (1,766.49 km) |
| Duncan to Redmond (Oregon) | 1,404.77 mi (2,260.76 km) |
| Duncan to Redmond (Washington) | 1,541.79 mi (2,481.27 km) |
| Duncan to Redondo Beach (California) | 1,167.89 mi (1,879.53 km) |
| Duncan to Redwood City (California) | 1,369.57 mi (2,204.11 km) |
| Duncan to Reedley (California) | 1,215.51 mi (1,956.18 km) |
