There are
2,779 mi
from Gaithersburg, MD to Pittsburg, CA
That's the driving distance. It would take 2 days to go from Gaithersburg, Maryland to Pittsburg, California.
The flight distance (direct flight from Gaithersburg, MD to Pittsburg, CA) is 2,389.81 mi.
2,779 mi = 4,472.13 kms