| South Portland to Duluth (Minnesota) | 1,081.94 mi (1,741.21 km) |
| South Portland to Dumas (Texas) | 1,753.98 mi (2,822.76 km) |
| South Portland to Dumont (New Jersey) | 265.01 mi (426.49 km) |
| South Portland to Duncan (Oklahoma) | 1,599.90 mi (2,574.79 km) |
| South Portland to Duncanville (Texas) | 1,623.71 mi (2,613.10 km) |
| South Portland to Dundalk (Maryland) | 440.24 mi (708.50 km) |
| South Portland to Dunedin (Florida) | 1,281.82 mi (2,062.89 km) |
| South Portland to Dunkirk (New York) | 463.17 mi (745.40 km) |
| South Portland to Dunmore (Pennsylvania) | 310.98 mi (500.47 km) |
| South Portland to Dunwoody (Georgia) | 1,006.69 mi (1,620.11 km) |
| South Portland to Durango (Colorado) | 2,006.65 mi (3,229.38 km) |
| South Portland to Durant (Oklahoma) | 1,546.25 mi (2,488.44 km) |
| South Portland to Durham (North Carolina) | 698.13 mi (1,123.53 km) |
| South Portland to Dyer (Indiana) | 886.91 mi (1,427.35 km) |
| South Portland to Dyersburg (Tennessee) | 1,136.49 mi (1,829.01 km) |
