| South Portland to Indianapolis (Indiana) | 858.59 mi (1,381.77 km) |
| South Portland to Indianola (Iowa) | 1,192.06 mi (1,918.44 km) |
| South Portland to Indio (California) | 2,535.95 mi (4,081.21 km) |
| South Portland to Inglewood (California) | 2,633.90 mi (4,238.86 km) |
| South Portland to Inkster (Michigan) | 664.34 mi (1,069.15 km) |
| South Portland to Inver Grove Heights (Minnesota) | 1,126.66 mi (1,813.19 km) |
| South Portland to Inwood (New York) | 273.23 mi (439.72 km) |
| South Portland to Iona (Florida) | 1,351.05 mi (2,174.30 km) |
| South Portland to Ionia (Michigan) | 743.70 mi (1,196.86 km) |
| South Portland to Iowa City (Iowa) | 1,085.11 mi (1,746.32 km) |
| South Portland to Irmo (South Carolina) | 880.33 mi (1,416.75 km) |
| South Portland to Irondale (Alabama) | 1,122.28 mi (1,806.13 km) |
| South Portland to Ironton (Ohio) | 734.02 mi (1,181.29 km) |
| South Portland to Irvine (California) | 2,614.87 mi (4,208.22 km) |
| South Portland to Irving (Texas) | 1,617.95 mi (2,603.83 km) |
