Located in the northwestern part from the center of Fukushima Prefecture, the lake is at 514 m height above sea level, with perimeters of 56 km and 103.3 km2 in area. Due to inflow of strongly acidic groundwater and rivers, the lake shows acidification, with low Chemical Oxygen Demand (COD) in the water and high degree of transparency. The surrounding wetlands include the one with the government designated Natural Monument Akaiyachishoya helophyte community mainly composed of Sphagnum.
