There are
1,050 mi
from Hereford, TX to Monrovia, CA
That's the driving distance. It would take 18 hours 3 mins to go from Hereford, Texas to Monrovia, California.
The flight distance (direct flight from Hereford, TX to Monrovia, CA) is 889.05 mi.
1,050 mi = 1,689.86 kms