There are
2,216 mi
from San Marcos, CA to Piqua, OH
That's the driving distance. It would take 1 day 15 hours to go from San Marcos, California to Piqua, Ohio.
The flight distance (direct flight from San Marcos, CA to Piqua, OH) is 1,876.46 mi.
2,216 mi = 3.22 kms