There are
2,648 mi
from San Leandro, CA to Niagara Falls, NY
That's the driving distance. It would take 1 day 22 hours to go from San Leandro, California to Niagara Falls, New York.
The flight distance (direct flight from San Leandro, CA to Niagara Falls, NY) is 2,273.06 mi.
2,648 mi = 3.22 kms