| Boise to Silver Firs (Washington) | 409.94 mi (659.73 km) |
| Boise to Silver Spring (Maryland) | 2,040.57 mi (3,283.98 km) |
| Boise to Silver Springs Shores (Florida) | 2,130.09 mi (3,428.04 km) |
| Boise to Silverdale (Washington) | 419.36 mi (674.89 km) |
| Boise to Silverton (Oregon) | 337.96 mi (543.89 km) |
| Boise to Simi Valley (California) | 658.89 mi (1,060.38 km) |
| Boise to Simpsonville (South Carolina) | 1,904.98 mi (3,065.77 km) |
| Boise to Sioux City (Iowa) | 1,002.30 mi (1,613.05 km) |
| Boise to Sioux Falls (South Dakota) | 973.92 mi (1,567.37 km) |
| Boise to Skokie (Illinois) | 1,440.88 mi (2,318.88 km) |
| Boise to Sleepy Hollow (New York) | 2,146.49 mi (3,454.44 km) |
| Boise to Slidell (Louisiana) | 1,714.38 mi (2,759.03 km) |
| Boise to Smithfield (North Carolina) | 2,074.21 mi (3,338.12 km) |
| Boise to Smithfield (Utah) | 254.64 mi (409.81 km) |
| Boise to Smithville (Missouri) | 1,154.16 mi (1,857.44 km) |
