There are
2,038 mi
from San Marcos, CA to Watertown, WI
That's the driving distance. It would take 1 day 12 hours to go from San Marcos, California to Watertown, Wisconsin.
The flight distance (direct flight from San Marcos, CA to Watertown, WI) is 1,682.85 mi.
2,038 mi = 3.22 kms