There are
828 mi
from Hayward, CA to Sammamish, WA
That's the driving distance. It would take 16 hours 1 min to go from Hayward, California to Sammamish, Washington.
The flight distance (direct flight from Hayward, CA to Sammamish, WA) is 689.07 mi.
828 mi = 1,332.36 kms