| Gaithersburg to Cascais | 3,553.92 mi (5,719.49 km) |
| Gaithersburg to Castelo Branco | 3,617.64 mi (5,822.03 km) |
| Gaithersburg to Castro Daire | 3,567.64 mi (5,741.56 km) |
| Gaithersburg to Celorico de Basto | 3,551.86 mi (5,716.17 km) |
| Gaithersburg to Chamusca | 3,582.23 mi (5,765.05 km) |
| Gaithersburg to Chaves | 3,568.02 mi (5,742.17 km) |
| Gaithersburg to Cinfaes | 3,552.77 mi (5,717.62 km) |
| Gaithersburg to Coimbra | 3,561.74 mi (5,732.07 km) |
| Gaithersburg to Condeixa-a-Nova | 3,560.80 mi (5,730.55 km) |
| Gaithersburg to Corroios | 3,569.43 mi (5,744.44 km) |
| Gaithersburg to Coruche | 3,590.84 mi (5,778.90 km) |
| Gaithersburg to Costa de Caparica | 3,564.41 mi (5,736.36 km) |
| Gaithersburg to Covilha | 3,605.00 mi (5,801.69 km) |
| Gaithersburg to Eiras | 3,561.17 mi (5,731.15 km) |
| Gaithersburg to Elvas | 3,661.11 mi (5,891.98 km) |
