| South Portland to Badger (Alaska) | 3,186.57 mi (5,128.29 km) |
| South Portland to Bailey's Crossroads (Virginia) | 485.02 mi (780.57 km) |
| South Portland to Bainbridge (Georgia) | 1,175.51 mi (1,891.79 km) |
| South Portland to Bainbridge Island (Washington) | 2,491.38 mi (4,009.48 km) |
| South Portland to Baker (Louisiana) | 1,453.99 mi (2,339.98 km) |
| South Portland to Bakersfield (California) | 2,622.34 mi (4,220.24 km) |
| South Portland to Balch Springs (Texas) | 1,606.68 mi (2,585.70 km) |
| South Portland to Baldwin (New York) | 266.95 mi (429.61 km) |
| South Portland to Baldwin (Pennsylvania) | 545.17 mi (877.37 km) |
| South Portland to Baldwin Park (California) | 2,611.04 mi (4,202.06 km) |
| South Portland to Ballenger Creek (Maryland) | 471.28 mi (758.45 km) |
| South Portland to Ballwin (Missouri) | 1,107.26 mi (1,781.96 km) |
| South Portland to Baltimore (Maryland) | 443.11 mi (713.12 km) |
| South Portland to Bangor (Maine) | 111.33 mi (179.17 km) |
| South Portland to Banning (California) | 2,562.01 mi (4,123.16 km) |
