Mildred Island is a submerged island in the San Joaquin River delta, in California. It is part of San Joaquin County. It flooded in 1983, and the land was abandoned. Its coordinates are . It appears on 1913 and 1952 United States Geological Survey maps of the area.
References | url = https://californiawaterblog.com/2013/06/17/the-delta-wont-rise-again/