| Southborough to Castle Rock (Colorado) | 4,727.79 mi (7,608.64 km) |
| Southborough to Castro Valley (California) | 5,376.43 mi (8,652.52 km) |
| Southborough to Catalina Foothills (Arizona) | 5,319.95 mi (8,561.63 km) |
| Southborough to Cataño (Puerto Rico) | 4,216.34 mi (6,785.54 km) |
| Southborough to Cathedral City (California) | 5,423.68 mi (8,728.57 km) |
| Southborough to Catonsville (Maryland) | 3,660.38 mi (5,890.81 km) |
| Southborough to Cave Spring (Virginia) | 3,886.49 mi (6,254.70 km) |
| Southborough to Cayce (South Carolina) | 4,083.30 mi (6,571.43 km) |
| Southborough to Cayey (Puerto Rico) | 4,233.97 mi (6,813.92 km) |
| Southborough to Cedar City (Utah) | 5,097.67 mi (8,203.90 km) |
| Southborough to Cedar Falls (Iowa) | 4,125.06 mi (6,638.65 km) |
| Southborough to Cedar Hill (Texas) | 4,790.28 mi (7,709.22 km) |
| Southborough to Cedar Lake (Indiana) | 3,990.02 mi (6,421.32 km) |
| Southborough to Cedar Mill (Oregon) | 4,944.76 mi (7,957.82 km) |
| Southborough to Cedar Park (Texas) | 4,931.20 mi (7,935.99 km) |
