| Harpenden to Carson (California) | 5,431.74 mi (8,741.55 km) |
| Harpenden to Carson City (Nevada) | 5,173.10 mi (8,325.30 km) |
| Harpenden to Carteret (New Jersey) | 3,459.98 mi (5,568.30 km) |
| Harpenden to Cartersville (Georgia) | 4,187.07 mi (6,738.43 km) |
| Harpenden to Carthage (Missouri) | 4,412.21 mi (7,100.77 km) |
| Harpenden to Cary (Illinois) | 3,936.92 mi (6,335.86 km) |
| Harpenden to Cary (North Carolina) | 3,866.02 mi (6,221.75 km) |
| Harpenden to Casa de Oro-Mount Helix (California) | 5,451.53 mi (8,773.40 km) |
| Harpenden to Casa Grande (Arizona) | 5,268.76 mi (8,479.25 km) |
| Harpenden to Casas Adobes (Arizona) | 5,274.19 mi (8,487.98 km) |
| Harpenden to Cascades (Virginia) | 3,656.66 mi (5,884.83 km) |
| Harpenden to Casper (Wyoming) | 4,546.88 mi (7,317.49 km) |
| Harpenden to Casselberry (Florida) | 4,316.47 mi (6,946.69 km) |
| Harpenden to Castaic (California) | 5,406.71 mi (8,701.26 km) |
| Harpenden to Castle Pines (Colorado) | 4,675.51 mi (7,524.51 km) |
