There are
1,272 mi
from Longmont, CO to Sammamish, WA
That's the driving distance. It would take 22 hours 7 mins to go from Longmont, Colorado to Sammamish, Washington.
The flight distance (direct flight from Longmont, CO to Sammamish, WA) is 987.27 mi.
1,272 mi = 1.61 kms