| Southborough to Caguas (Puerto Rico) | 4,222.53 mi (6,795.50 km) |
| Southborough to Cahokia (Illinois) | 4,228.47 mi (6,805.07 km) |
| Southborough to Calabasas (California) | 5,477.89 mi (8,815.82 km) |
| Southborough to Caldwell (Idaho) | 4,878.28 mi (7,850.84 km) |
| Southborough to Caledonia (Wisconsin) | 3,940.74 mi (6,342.01 km) |
| Southborough to Calera (Alabama) | 4,357.09 mi (7,012.06 km) |
| Southborough to Calexico (California) | 5,456.71 mi (8,781.73 km) |
| Southborough to Calhoun (Georgia) | 4,217.04 mi (6,786.66 km) |
| Southborough to California (Maryland) | 3,693.46 mi (5,944.05 km) |
| Southborough to California City (California) | 5,394.13 mi (8,681.01 km) |
| Southborough to Callaway (Florida) | 4,456.34 mi (7,171.78 km) |
| Southborough to Calumet City (Illinois) | 3,983.00 mi (6,410.02 km) |
| Southborough to Calverton (Maryland) | 3,678.04 mi (5,919.24 km) |
| Southborough to Camano (Washington) | 4,784.17 mi (7,699.38 km) |
| Southborough to Camarillo (California) | 5,484.56 mi (8,826.55 km) |
