| Difficult Run to Salisbury (New York) | 237.89 mi (382.84 km) |
| Difficult Run to Salisbury (North Carolina) | 282.53 mi (454.68 km) |
| Difficult Run to Salmon Creek (Washington) | 2,330.57 mi (3,750.69 km) |
| Difficult Run to Salt Lake City (Utah) | 1,827.46 mi (2,941.02 km) |
| Difficult Run to Sammamish (Washington) | 2,293.83 mi (3,691.57 km) |
| Difficult Run to San Angelo (Texas) | 1,398.04 mi (2,249.92 km) |
| Difficult Run to San Anselmo (California) | 2,422.62 mi (3,898.83 km) |
| Difficult Run to San Antonio (Texas) | 1,370.09 mi (2,204.94 km) |
| Difficult Run to San Benito (Texas) | 1,469.68 mi (2,365.23 km) |
| Difficult Run to San Bernardino (California) | 2,224.45 mi (3,579.90 km) |
| Difficult Run to San Bruno (California) | 2,422.20 mi (3,898.16 km) |
| Difficult Run to San Buenaventura (California) | 2,325.06 mi (3,741.83 km) |
| Difficult Run to San Carlos (California) | 2,416.10 mi (3,888.34 km) |
| Difficult Run to San Carlos Park (Florida) | 896.68 mi (1,443.07 km) |
| Difficult Run to San Clemente (California) | 2,258.39 mi (3,634.54 km) |
