| South Portland to Clemson (South Carolina) | 910.42 mi (1,465.17 km) |
| South Portland to Clermont (Florida) | 1,220.29 mi (1,963.87 km) |
| South Portland to Cleveland (Mississippi) | 1,291.46 mi (2,078.40 km) |
| South Portland to Cleveland (Ohio) | 598.04 mi (962.45 km) |
| South Portland to Cleveland (Tennessee) | 970.63 mi (1,562.07 km) |
| South Portland to Cleveland Heights (Ohio) | 591.54 mi (951.99 km) |
| South Portland to Cliffside Park (New Jersey) | 270.99 mi (436.12 km) |
| South Portland to Clifton (Colorado) | 1,986.71 mi (3,197.30 km) |
| South Portland to Clifton (New Jersey) | 275.10 mi (442.74 km) |
| South Portland to Clinton (Iowa) | 1,017.50 mi (1,637.51 km) |
| South Portland to Clinton (Maryland) | 481.46 mi (774.84 km) |
| South Portland to Clinton (Mississippi) | 1,335.50 mi (2,149.29 km) |
| South Portland to Clinton (Utah) | 2,116.41 mi (3,406.03 km) |
| South Portland to Clive (Iowa) | 1,199.21 mi (1,929.95 km) |
| South Portland to Cloquet (Minnesota) | 1,098.41 mi (1,767.72 km) |
