| Southborough to Caño Martin Peña (Puerto Rico) | 4,212.67 mi (6,779.63 km) |
| Southborough to Cañon City (Colorado) | 4,789.66 mi (7,708.22 km) |
| Southborough to Canóvanas (Puerto Rico) | 4,209.43 mi (6,774.42 km) |
| Southborough to Canton (Georgia) | 4,210.56 mi (6,776.24 km) |
| Southborough to Canton (Illinois) | 4,127.47 mi (6,642.51 km) |
| Southborough to Canton (Mississippi) | 4,516.09 mi (7,267.94 km) |
| Southborough to Canton (Ohio) | 3,778.21 mi (6,080.44 km) |
| Southborough to Canyon (Texas) | 4,852.52 mi (7,809.38 km) |
| Southborough to Canyon Lake (California) | 5,458.16 mi (8,784.05 km) |
| Southborough to Canyon Lake (Texas) | 4,981.60 mi (8,017.11 km) |
| Southborough to Cape Coral (Florida) | 4,481.61 mi (7,212.45 km) |
| Southborough to Cape Girardeau (Missouri) | 4,265.05 mi (6,863.93 km) |
| Southborough to Carbondale (Illinois) | 4,232.00 mi (6,810.75 km) |
| Southborough to Carlisle (Pennsylvania) | 3,637.77 mi (5,854.43 km) |
| Southborough to Carlsbad (California) | 5,490.97 mi (8,836.86 km) |
