| San Marcos to Silver Firs (Washington) | 1,050.10 mi (1,689.97 km) |
| San Marcos to Silver Spring (Maryland) | 2,260.22 mi (3,637.48 km) |
| San Marcos to Silver Springs Shores (Florida) | 2,088.31 mi (3,360.81 km) |
| San Marcos to Silverdale (Washington) | 1,044.31 mi (1,680.66 km) |
| San Marcos to Silverton (Oregon) | 872.84 mi (1,404.71 km) |
| San Marcos to Simi Valley (California) | 119.59 mi (192.47 km) |
| San Marcos to Simpsonville (South Carolina) | 1,994.70 mi (3,210.17 km) |
| San Marcos to Sioux City (Iowa) | 1,300.74 mi (2,093.34 km) |
| San Marcos to Sioux Falls (South Dakota) | 1,315.11 mi (2,116.46 km) |
| San Marcos to Skokie (Illinois) | 1,714.47 mi (2,759.17 km) |
| San Marcos to Sleepy Hollow (New York) | 2,422.39 mi (3,898.46 km) |
| San Marcos to Slidell (Louisiana) | 1,617.35 mi (2,602.88 km) |
| San Marcos to Smithfield (North Carolina) | 2,207.26 mi (3,552.23 km) |
| San Marcos to Smithfield (Utah) | 668.44 mi (1,075.75 km) |
| San Marcos to Smithville (Missouri) | 1,326.90 mi (2,135.45 km) |
