There are
304 mi
from Gaithersburg, MD to Poughkeepsie, NY
That's the driving distance. It would take 6 hours 17 mins to go from Gaithersburg, Maryland to Poughkeepsie, New York.
The flight distance (direct flight from Gaithersburg, MD to Poughkeepsie, NY) is 246.92 mi.
304 mi = 489.80 kms