| South Portland to Isabela (Puerto Rico) | 1,746.82 mi (2,811.23 km) |
| South Portland to Iselin (New Jersey) | 295.52 mi (475.59 km) |
| South Portland to Isla Vista (California) | 2,694.35 mi (4,336.13 km) |
| South Portland to Issaquah (Washington) | 2,470.49 mi (3,975.87 km) |
| South Portland to Ithaca (New York) | 324.24 mi (521.82 km) |
| South Portland to Ives Estates (Florida) | 1,341.22 mi (2,158.48 km) |
| South Portland to Jackson (Michigan) | 719.47 mi (1,157.87 km) |
| South Portland to Jackson (Mississippi) | 1,331.67 mi (2,143.12 km) |
| South Portland to Jackson (Missouri) | 1,101.76 mi (1,773.11 km) |
| South Portland to Jackson (Tennessee) | 1,126.56 mi (1,813.02 km) |
| South Portland to Jackson (Wyoming) | 2,006.86 mi (3,229.72 km) |
| South Portland to Jacksonville (Alabama) | 1,071.88 mi (1,725.03 km) |
| South Portland to Jacksonville (Arkansas) | 1,310.07 mi (2,108.35 km) |
| South Portland to Jacksonville (Florida) | 1,110.82 mi (1,787.69 km) |
| South Portland to Jacksonville (Illinois) | 1,060.93 mi (1,707.40 km) |
