There are
3,071 mi
from Manchester, NH to Seatac, WA
That's the driving distance. It would take 2 days 7 hours to go from Manchester, New Hampshire to Seatac, Washington.
The flight distance (direct flight from Manchester, NH to Seatac, WA) is 2,449.93 mi.
3,071 mi = 4,942.65 kms