| South Portland to Brown Deer (Wisconsin) | 886.68 mi (1,426.97 km) |
| South Portland to Brownsburg (Indiana) | 868.65 mi (1,397.96 km) |
| South Portland to Brownsville (Florida) | 1,351.66 mi (2,175.28 km) |
| South Portland to Brownsville (Texas) | 1,949.00 mi (3,136.61 km) |
| South Portland to Brownwood (Texas) | 1,759.31 mi (2,831.34 km) |
| South Portland to Brunswick (Georgia) | 1,056.76 mi (1,700.69 km) |
| South Portland to Brunswick (Ohio) | 610.01 mi (981.71 km) |
| South Portland to Brushy Creek (Texas) | 1,751.57 mi (2,818.88 km) |
| South Portland to Bryan (Texas) | 1,682.28 mi (2,707.36 km) |
| South Portland to Bryant (Arkansas) | 1,337.33 mi (2,152.23 km) |
| South Portland to Bryn Mawr-Skyway (Washington) | 2,480.08 mi (3,991.30 km) |
| South Portland to Buckeye (Arizona) | 2,366.77 mi (3,808.95 km) |
| South Portland to Buckhall (Virginia) | 503.16 mi (809.76 km) |
| South Portland to Bucyrus (Ohio) | 676.89 mi (1,089.36 km) |
| South Portland to Buda (Texas) | 1,775.72 mi (2,857.74 km) |
