Acker Island
Acker Island (also known as Lost Isle) is a small island in the Sacramento–San Joaquin River Delta. It is part of San Joaquin County, California. Its coordinates are 37°59′51″N 121°26′56″W / 37.99750°N 121.44889°W, and the United States Geological Survey measured its elevation as 3 ft (0.91 m) in 1981. It appears on a 1952 USGS map of the area.