Lake Bonney SE, also known locally as Coonunda or Canunda, is a large coastal freshwater lake situated in the Limestone Coast region of South Australia, approximately 450 km southeast of Adelaide and just 13 km southwest of Millicent. Covering a surface area of 79 square kilometres, it ranks among the largest freshwater bodies in the country, stretching roughly 23 km in length and up to 4 km wide. The lake sits within the gazetted locality of Canunda and is bordered by the Canunda National Park along its shores, creating a scenic and ecologically rich setting for anglers and nature enthusiasts alike. With an average depth of around 3 metres, the lake is relatively shallow throughout, characteristic of the low-lying limestone coastal landscape of the region. The lake is classified as brackish freshwater, fed by natural inflows from a catchment area of approximately 430 square kilometres, with water ultimately draining toward the Southern Ocean through evaporation and outflow.