| Keystone to Smyrna (Delaware) | 868.92 mi (1,398.40 km) |
| Keystone to Smyrna (Georgia) | 411.97 mi (663.01 km) |
| Keystone to Smyrna (Tennessee) | 588.16 mi (946.55 km) |
| Keystone to Snellville (Georgia) | 404.19 mi (650.48 km) |
| Keystone to Snoqualmie (Washington) | 2,487.79 mi (4,003.71 km) |
| Keystone to Snyder (Texas) | 1,134.30 mi (1,825.48 km) |
| Keystone to Socastee (South Carolina) | 438.87 mi (706.29 km) |
| Keystone to Socorro (Texas) | 1,435.02 mi (2,309.44 km) |
| Keystone to Soddy-Daisy (Tennessee) | 515.02 mi (828.84 km) |
| Keystone to Solana Beach (California) | 2,079.63 mi (3,346.84 km) |
| Keystone to Soledad (California) | 2,318.12 mi (3,730.65 km) |
| Keystone to Solon (Ohio) | 918.19 mi (1,477.68 km) |
| Keystone to Somers Point (New Jersey) | 898.11 mi (1,445.38 km) |
| Keystone to Somerset (Kentucky) | 629.46 mi (1,013.03 km) |
| Keystone to Somerset (New Jersey) | 970.98 mi (1,562.64 km) |
