There are
1,146 mi
from Billings, MT to Clearlake, CA
That's the driving distance. It would take 21 hours 8 mins to go from Billings, Montana to Clearlake, California.
The flight distance (direct flight from Billings, MT to Clearlake, CA) is 859.60 mi.
1,146 mi = 1.61 kms