| Potomac to Coudekerque-Branche | 3,779.99 mi (6,083.31 km) |
| Potomac to Coueron | 3,698.55 mi (5,952.25 km) |
| Potomac to Coulommiers | 3,864.57 mi (6,219.43 km) |
| Potomac to Courbevoic | 3,827.46 mi (6,159.71 km) |
| Potomac to Courcouronnes | 3,842.00 mi (6,183.10 km) |
| Potomac to Cournon-d'Auvergne | 3,953.73 mi (6,362.91 km) |
| Potomac to Courrieres | 3,816.68 mi (6,142.35 km) |
| Potomac to Coutras | 3,825.37 mi (6,156.34 km) |
| Potomac to Couzeix | 3,863.67 mi (6,217.98 km) |
| Potomac to Cran-Gevrier | 4,075.78 mi (6,559.33 km) |
| Potomac to Craponne | 4,020.47 mi (6,470.32 km) |
| Potomac to Creil | 3,827.87 mi (6,160.37 km) |
| Potomac to Crepy-en-Valois | 3,845.41 mi (6,188.58 km) |
| Potomac to Crest | 4,063.85 mi (6,540.13 km) |
| Potomac to Creteil | 3,839.06 mi (6,178.38 km) |
