| Harpenden to Caguas (Puerto Rico) | 4,201.75 mi (6,762.06 km) |
| Harpenden to Cahokia (Illinois) | 4,184.42 mi (6,734.18 km) |
| Harpenden to Calabasas (California) | 5,427.67 mi (8,735.00 km) |
| Harpenden to Caldwell (Idaho) | 4,827.02 mi (7,768.33 km) |
| Harpenden to Caledonia (Wisconsin) | 3,895.61 mi (6,269.38 km) |
| Harpenden to Calera (Alabama) | 4,316.64 mi (6,946.96 km) |
| Harpenden to Calexico (California) | 5,407.41 mi (8,702.38 km) |
| Harpenden to Calhoun (Georgia) | 4,176.66 mi (6,721.68 km) |
| Harpenden to California (Maryland) | 3,654.39 mi (5,881.18 km) |
| Harpenden to California City (California) | 5,343.90 mi (8,600.18 km) |
| Harpenden to Callaway (Florida) | 4,417.79 mi (7,109.75 km) |
| Harpenden to Calumet City (Illinois) | 3,938.47 mi (6,338.36 km) |
| Harpenden to Calverton (Maryland) | 3,638.36 mi (5,855.38 km) |
| Harpenden to Camano (Washington) | 4,731.90 mi (7,615.26 km) |
| Harpenden to Camarillo (California) | 5,434.26 mi (8,745.60 km) |
