There are
836 mi
from San Mateo, CA to Sammamish, WA
That's the driving distance. It would take 16 hours 13 mins to go from San Mateo, California to Sammamish, Washington.
The flight distance (direct flight from San Mateo, CA to Sammamish, WA) is 696.49 mi.
836 mi = 1,346.04 kms