| South Portland to Castle Pines (Colorado) | 1,797.93 mi (2,893.49 km) |
| South Portland to Castle Rock (Colorado) | 1,799.17 mi (2,895.49 km) |
| South Portland to Castro Valley (California) | 2,699.53 mi (4,344.47 km) |
| South Portland to Catalina Foothills (Arizona) | 2,318.87 mi (3,731.86 km) |
| South Portland to Cataño (Puerto Rico) | 1,757.33 mi (2,828.16 km) |
| South Portland to Cathedral City (California) | 2,543.98 mi (4,094.14 km) |
| South Portland to Catonsville (Maryland) | 449.97 mi (724.15 km) |
| South Portland to Cave Spring (Virginia) | 675.26 mi (1,086.73 km) |
| South Portland to Cayce (South Carolina) | 883.43 mi (1,421.75 km) |
| South Portland to Cayey (Puerto Rico) | 1,779.30 mi (2,863.51 km) |
| South Portland to Cedar City (Utah) | 2,255.38 mi (3,629.68 km) |
| South Portland to Cedar Falls (Iowa) | 1,117.92 mi (1,799.11 km) |
| South Portland to Cedar Hill (Texas) | 1,628.52 mi (2,620.85 km) |
| South Portland to Cedar Lake (Indiana) | 885.80 mi (1,425.55 km) |
| South Portland to Cedar Mill (Oregon) | 2,540.77 mi (4,088.98 km) |
