| South Portland to Baraboo (Wisconsin) | 971.73 mi (1,563.85 km) |
| South Portland to Barberton (Ohio) | 605.15 mi (973.89 km) |
| South Portland to Bardstown (Kentucky) | 888.05 mi (1,429.18 km) |
| South Portland to Barrington (Illinois) | 907.00 mi (1,459.67 km) |
| South Portland to Barstow (California) | 2,538.85 mi (4,085.88 km) |
| South Portland to Bartlesville (Oklahoma) | 1,428.69 mi (2,299.26 km) |
| South Portland to Bartlett (Illinois) | 913.58 mi (1,470.27 km) |
| South Portland to Bartlett (Tennessee) | 1,188.58 mi (1,912.83 km) |
| South Portland to Bartow (Florida) | 1,262.60 mi (2,031.96 km) |
| South Portland to Batavia (Illinois) | 920.91 mi (1,482.05 km) |
| South Portland to Batavia (New York) | 398.93 mi (642.01 km) |
| South Portland to Batesville (Arkansas) | 1,252.58 mi (2,015.82 km) |
| South Portland to Baton Rouge (Louisiana) | 1,459.65 mi (2,349.07 km) |
| South Portland to Battle Creek (Michigan) | 759.92 mi (1,222.97 km) |
| South Portland to Battle Ground (Washington) | 2,524.10 mi (4,062.15 km) |
