| Duncan to Storm Lake (Iowa) | 578.75 mi (931.41 km) |
| Duncan to Storrs (Connecticut) | 1,475.21 mi (2,374.12 km) |
| Duncan to Stoughton (Wisconsin) | 744.30 mi (1,197.84 km) |
| Duncan to Stow (Ohio) | 1,007.20 mi (1,620.93 km) |
| Duncan to Streamwood (Illinois) | 738.23 mi (1,188.07 km) |
| Duncan to Streator (Illinois) | 672.40 mi (1,082.13 km) |
| Duncan to Streetsboro (Ohio) | 1,013.10 mi (1,630.43 km) |
| Duncan to Strongsville (Ohio) | 991.71 mi (1,596.00 km) |
| Duncan to Stuart (Florida) | 1,162.40 mi (1,870.70 km) |
| Duncan to Stuarts Draft (Virginia) | 1,076.98 mi (1,733.23 km) |
| Duncan to Sturgis (Michigan) | 842.80 mi (1,356.35 km) |
| Duncan to Suamico (Wisconsin) | 871.36 mi (1,402.32 km) |
| Duncan to Sudley (Virginia) | 1,166.70 mi (1,877.62 km) |
| Duncan to Suffern (New York) | 1,369.67 mi (2,204.28 km) |
| Duncan to Suffolk (Virginia) | 1,202.06 mi (1,934.52 km) |
