Winnetka is a neighborhood located in the San Fernando Valley region of Los Angeles, California. It is situated in the western part of the San Fernando Valley, bordered by Reseda to the west, Canoga Park to the north, Woodland Hills to the east, and Tarzana to the south. The 2000 U.S. census counted 40,943 residents in the 4.78-square-mile Winnetka neighborhood.