There are
1,776 mi
from San Bernardino, CA to Clayton, MO
That's the driving distance. It would take 1 day 6 hours to go from San Bernardino, California to Clayton, Missouri.
The flight distance (direct flight from San Bernardino, CA to Clayton, MO) is 1,526.67 mi.
1,776 mi = 2,858.93 kms