| Rockville to Darby (Pennsylvania) | 116.39 mi (187.32 km) |
| Rockville to Dardenne Prairie (Missouri) | 729.50 mi (1,174.01 km) |
| Rockville to Darien (Illinois) | 598.02 mi (962.41 km) |
| Rockville to Davenport (Iowa) | 728.02 mi (1,171.64 km) |
| Rockville to Davidson (North Carolina) | 320.15 mi (515.24 km) |
| Rockville to Davie (Florida) | 916.66 mi (1,475.22 km) |
| Rockville to Davis (California) | 2,375.58 mi (3,823.13 km) |
| Rockville to Dayton (Nevada) | 2,250.41 mi (3,621.68 km) |
| Rockville to Dayton (Ohio) | 378.94 mi (609.84 km) |
| Rockville to Daytona Beach (Florida) | 718.96 mi (1,157.05 km) |
| Rockville to De Pere (Wisconsin) | 672.51 mi (1,082.30 km) |
| Rockville to De Witt (New York) | 278.35 mi (447.96 km) |
| Rockville to Dearborn (Michigan) | 387.75 mi (624.03 km) |
| Rockville to Dearborn Heights (Michigan) | 390.63 mi (628.66 km) |
| Rockville to DeBary (Florida) | 744.00 mi (1,197.35 km) |
