| Boulder to Dover (New Jersey) | 1,606.44 mi (2,585.32 km) |
| Boulder to Dover (Ohio) | 1,249.76 mi (2,011.30 km) |
| Boulder to Downers Grove (Illinois) | 906.67 mi (1,459.15 km) |
| Boulder to Downey (California) | 824.68 mi (1,327.19 km) |
| Boulder to Dranesville (Virginia) | 1,481.98 mi (2,385.01 km) |
| Boulder to Draper (Utah) | 349.85 mi (563.03 km) |
| Boulder to Drexel Heights (Arizona) | 632.98 mi (1,018.68 km) |
| Boulder to Drexel Hill (Pennsylvania) | 1,577.88 mi (2,539.35 km) |
| Boulder to Duarte (California) | 807.47 mi (1,299.50 km) |
| Boulder to Dublin (California) | 908.03 mi (1,461.34 km) |
| Boulder to Dublin (Georgia) | 1,342.08 mi (2,159.86 km) |
| Boulder to Dublin (Ohio) | 1,165.91 mi (1,876.35 km) |
| Boulder to Dubuque (Iowa) | 773.51 mi (1,244.85 km) |
| Boulder to Duluth (Georgia) | 1,232.68 mi (1,983.80 km) |
| Boulder to Duluth (Minnesota) | 805.09 mi (1,295.67 km) |
