| Boulder to Somersworth (New Hampshire) | 1,775.89 mi (2,858.02 km) |
| Boulder to Somerton (Arizona) | 733.84 mi (1,181.01 km) |
| Boulder to Somerville (Massachusetts) | 1,770.72 mi (2,849.70 km) |
| Boulder to Somerville (New Jersey) | 1,607.07 mi (2,586.32 km) |
| Boulder to Sonoma (California) | 928.18 mi (1,493.76 km) |
| Boulder to Soquel (California) | 925.06 mi (1,488.74 km) |
| Boulder to South Bend (Indiana) | 996.60 mi (1,603.87 km) |
| Boulder to South Bradenton (Florida) | 1,557.93 mi (2,507.24 km) |
| Boulder to South Burlington (Vermont) | 1,655.84 mi (2,664.81 km) |
| Boulder to South Charleston (West Virginia) | 1,262.20 mi (2,031.31 km) |
| Boulder to South Daytona (Florida) | 1,562.59 mi (2,514.74 km) |
| Boulder to South El Monte (California) | 816.43 mi (1,313.92 km) |
| Boulder to South Elgin (Illinois) | 892.05 mi (1,435.62 km) |
| Boulder to South Euclid (Ohio) | 1,241.92 mi (1,998.68 km) |
| Boulder to South Farmingdale (New York) | 1,665.70 mi (2,680.69 km) |
