| South Portland to Commerce (California) | 2,622.94 mi (4,221.21 km) |
| South Portland to Commerce City (Colorado) | 1,786.99 mi (2,875.88 km) |
| South Portland to Compton (California) | 2,630.21 mi (4,232.91 km) |
| South Portland to Comstock Park (Michigan) | 773.27 mi (1,244.45 km) |
| South Portland to Concord (California) | 2,688.72 mi (4,327.07 km) |
| South Portland to Concord (Missouri) | 1,100.26 mi (1,770.69 km) |
| South Portland to Concord (New Hampshire) | 69.47 mi (111.80 km) |
| South Portland to Concord (North Carolina) | 791.36 mi (1,273.57 km) |
| South Portland to Conneaut (Ohio) | 534.02 mi (859.42 km) |
| South Portland to Connersville (Indiana) | 813.08 mi (1,308.53 km) |
| South Portland to Conroe (Texas) | 1,656.53 mi (2,665.92 km) |
| South Portland to Converse (Texas) | 1,821.95 mi (2,932.14 km) |
| South Portland to Conway (Arkansas) | 1,318.58 mi (2,122.05 km) |
| South Portland to Conway (Florida) | 1,211.45 mi (1,949.65 km) |
| South Portland to Conway (South Carolina) | 823.68 mi (1,325.59 km) |
