| Difficult Run to Dover (New Jersey) | 201.55 mi (324.36 km) |
| Difficult Run to Dover (Ohio) | 246.80 mi (397.18 km) |
| Difficult Run to Downers Grove (Illinois) | 595.87 mi (958.95 km) |
| Difficult Run to Downey (California) | 2,274.25 mi (3,660.05 km) |
| Difficult Run to Dranesville (Virginia) | 6.60 mi (10.62 km) |
| Difficult Run to Draper (Utah) | 1,826.38 mi (2,939.27 km) |
| Difficult Run to Drexel Heights (Arizona) | 1,939.90 mi (3,121.96 km) |
| Difficult Run to Drexel Hill (Pennsylvania) | 130.89 mi (210.65 km) |
| Difficult Run to Duarte (California) | 2,259.16 mi (3,635.76 km) |
| Difficult Run to Dublin (California) | 2,392.36 mi (3,850.14 km) |
| Difficult Run to Dublin (Georgia) | 539.60 mi (868.40 km) |
| Difficult Run to Dublin (Ohio) | 320.13 mi (515.21 km) |
| Difficult Run to Dubuque (Iowa) | 741.68 mi (1,193.62 km) |
| Difficult Run to Duluth (Georgia) | 507.01 mi (815.96 km) |
| Difficult Run to Duluth (Minnesota) | 923.59 mi (1,486.38 km) |
