| Rockville to Duluth (Minnesota) | 923.29 mi (1,485.89 km) |
| Rockville to Dumas (Texas) | 1,374.09 mi (2,211.39 km) |
| Rockville to Dumont (New Jersey) | 211.07 mi (339.69 km) |
| Rockville to Duncan (Oklahoma) | 1,187.84 mi (1,911.65 km) |
| Rockville to Duncanville (Texas) | 1,189.20 mi (1,913.83 km) |
| Rockville to Dundalk (Maryland) | 37.69 mi (60.66 km) |
| Rockville to Dunedin (Florida) | 829.03 mi (1,334.19 km) |
| Rockville to Dunkirk (New York) | 260.84 mi (419.79 km) |
| Rockville to Dunmore (Pennsylvania) | 180.61 mi (290.66 km) |
| Rockville to Dunwoody (Georgia) | 532.73 mi (857.35 km) |
| Rockville to Durango (Colorado) | 1,665.53 mi (2,680.41 km) |
| Rockville to Durant (Oklahoma) | 1,121.70 mi (1,805.21 km) |
| Rockville to Durham (North Carolina) | 234.85 mi (377.96 km) |
| Rockville to Dyer (Indiana) | 570.18 mi (917.61 km) |
| Rockville to Dyersburg (Tennessee) | 700.85 mi (1,127.91 km) |
