There are
1,095 mi
from Longmont, CO to Susanville, CA
That's the driving distance. It would take 18 hours 31 mins to go from Longmont, Colorado to Susanville, California.
The flight distance (direct flight from Longmont, CO to Susanville, CA) is 818.69 mi.
1,095 mi = 1.61 kms