There are
2,078 mi
from San Marcos, CA to Greenfield, WI
That's the driving distance. It would take 1 day 12 hours to go from San Marcos, California to Greenfield, Wisconsin.
The flight distance (direct flight from San Marcos, CA to Greenfield, WI) is 1,713.96 mi.
2,078 mi = 3.22 kms