| Potomac to Collegno | 4,164.87 mi (6,702.71 km) |
| Potomac to Cologno al Serio | 4,240.48 mi (6,824.39 km) |
| Potomac to Cologno Monzese | 4,224.19 mi (6,798.18 km) |
| Potomac to Colorno | 4,291.00 mi (6,905.69 km) |
| Potomac to Comacchio | 4,375.93 mi (7,042.38 km) |
| Potomac to Comiso | 4,764.89 mi (7,668.35 km) |
| Potomac to Como | 4,206.96 mi (6,770.44 km) |
| Potomac to Concordia Sagittaria | 4,367.80 mi (7,029.29 km) |
| Potomac to Concorezzo | 4,224.70 mi (6,798.99 km) |
| Potomac to Conegliano | 4,340.54 mi (6,985.42 km) |
| Potomac to Conselice | 4,367.20 mi (7,028.33 km) |
| Potomac to Conselve | 4,344.35 mi (6,991.56 km) |
| Potomac to Conversano | 4,723.88 mi (7,602.35 km) |
| Potomac to Copertino | 4,791.48 mi (7,711.14 km) |
| Potomac to Copparo | 4,354.19 mi (7,007.40 km) |
