| Gaithersburg to Hilliard (Ohio) | 322.54 mi (519.08 km) |
| Gaithersburg to Hillsboro (Oregon) | 2,344.17 mi (3,772.58 km) |
| Gaithersburg to Hillsborough (California) | 2,423.36 mi (3,900.01 km) |
| Gaithersburg to Hillsborough (New Jersey) | 165.69 mi (266.65 km) |
| Gaithersburg to Hilo (Hawaii) | 4,734.78 mi (7,619.89 km) |
| Gaithersburg to Hilton Head Island (South Carolina) | 519.18 mi (835.54 km) |
| Gaithersburg to Hinesville (Georgia) | 562.29 mi (904.91 km) |
| Gaithersburg to Hinsdale (Illinois) | 592.06 mi (952.83 km) |
| Gaithersburg to Hobart (Indiana) | 554.44 mi (892.29 km) |
| Gaithersburg to Hobbs (New Mexico) | 1,511.61 mi (2,432.70 km) |
| Gaithersburg to Hobe Sound (Florida) | 850.31 mi (1,368.44 km) |
| Gaithersburg to Hoboken (New Jersey) | 202.10 mi (325.24 km) |
| Gaithersburg to Hockessin (Delaware) | 93.20 mi (149.99 km) |
| Gaithersburg to Hoffman Estates (Illinois) | 607.72 mi (978.03 km) |
| Gaithersburg to Holbrook (New York) | 247.53 mi (398.36 km) |
