| Boulder to San Luis Obispo (California) | 903.70 mi (1,454.36 km) |
| Boulder to San Marcos (California) | 813.75 mi (1,309.61 km) |
| Boulder to San Marcos (Texas) | 813.92 mi (1,309.88 km) |
| Boulder to San Marino (California) | 816.69 mi (1,314.34 km) |
| Boulder to San Mateo (California) | 932.99 mi (1,501.50 km) |
| Boulder to San Pablo (California) | 927.26 mi (1,492.28 km) |
| Boulder to San Rafael (California) | 936.27 mi (1,506.79 km) |
| Boulder to San Ramon (California) | 909.32 mi (1,463.40 km) |
| Boulder to San Tan Valley (Arizona) | 588.09 mi (946.43 km) |
| Boulder to Sand Springs (Oklahoma) | 563.91 mi (907.53 km) |
| Boulder to Sandusky (Ohio) | 1,181.30 mi (1,901.12 km) |
| Boulder to Sandy (Oregon) | 937.96 mi (1,509.50 km) |
| Boulder to Sandy (Utah) | 349.66 mi (562.73 km) |
| Boulder to Sandy Springs (Georgia) | 1,223.37 mi (1,968.83 km) |
| Boulder to Sanford (Florida) | 1,564.46 mi (2,517.75 km) |
