Little Mandeville Island is a small, mostly submerged island in the San Joaquin River delta, in California. It is part of San Joaquin County, and its coordinates are 38°00′38″N 121°33′54″W / 38.0104776°N 121.5649522°W / 38.0104776; -121.5649522 (Little Mandeville Island). In 1994, 376 acres (152 ha) of former farmland was inundated with water after a levee broke.