| Portland to Cortona | 5,698.58 mi (9,170.98 km) |
| Portland to Cosenza | 6,045.78 mi (9,729.75 km) |
| Portland to Cossato | 5,465.23 mi (8,795.44 km) |
| Portland to Costa Volpino | 5,499.35 mi (8,850.35 km) |
| Portland to Creazzo | 5,551.44 mi (8,934.19 km) |
| Portland to Crema | 5,516.09 mi (8,877.29 km) |
| Portland to Cremona | 5,538.75 mi (8,913.76 km) |
| Portland to Crevalcore | 5,591.64 mi (8,998.88 km) |
| Portland to Crispiano | 5,989.64 mi (9,639.40 km) |
| Portland to Crosia | 6,042.05 mi (9,723.74 km) |
| Portland to Crotone | 6,080.30 mi (9,785.30 km) |
| Portland to Cuneo | 5,517.64 mi (8,879.78 km) |
| Portland to Cuorgne | 5,461.94 mi (8,790.14 km) |
| Portland to Cusano Milanino | 5,492.54 mi (8,839.38 km) |
| Portland to Cutro | 6,080.15 mi (9,785.05 km) |
