There are
2,281 mi
from San Marcos, CA to Chillicothe, OH
That's the driving distance. It would take 1 day 16 hours to go from San Marcos, California to Chillicothe, Ohio.
The flight distance (direct flight from San Marcos, CA to Chillicothe, OH) is 1,940.18 mi.
2,281 mi = 3.22 kms