| Duncan to Southern Pines (North Carolina) | 1,049.21 mi (1,688.54 km) |
| Duncan to Southfield (Michigan) | 961.62 mi (1,547.58 km) |
| Duncan to Southgate (Michigan) | 954.85 mi (1,536.68 km) |
| Duncan to Southlake (Texas) | 118.22 mi (190.25 km) |
| Duncan to Spanaway (Washington) | 1,536.88 mi (2,473.36 km) |
| Duncan to Spanish Fork (Utah) | 844.99 mi (1,359.88 km) |
| Duncan to Spanish Lake (Missouri) | 518.25 mi (834.04 km) |
| Duncan to Spanish Springs (Nevada) | 1,245.96 mi (2,005.18 km) |
| Duncan to Sparks (Nevada) | 1,247.47 mi (2,007.61 km) |
| Duncan to Spartanburg (South Carolina) | 907.66 mi (1,460.74 km) |
| Duncan to Spearfish (South Dakota) | 755.34 mi (1,215.61 km) |
| Duncan to Speedway (Indiana) | 737.23 mi (1,186.46 km) |
| Duncan to Spencer (Iowa) | 612.89 mi (986.35 km) |
| Duncan to Spokane (Washington) | 1,354.71 mi (2,180.20 km) |
| Duncan to Spokane Valley (Washington) | 1,346.98 mi (2,167.76 km) |
