Lake Te Anau (Māori: Te Ana-au) is in the southwest of New Zealand’s South Island and is the second-largest lake in the country, as well as the largest in the South Island. It is also one of the largest freshwater lakes in Australasia by volume. The lake runs 65 km from north to south and has three long western arms: North Fiord, Middle Fiord, and South Fiord. These are New Zealand’s only inland fiords. Several small islands sit at the entrance to Middle Fiord, which later divides into two branches. Lake Te Anau sits 210 metres above sea level and reaches a depth of 425 metres, placing much of its lakebed below sea level. Control gates at the southern end regulate the flow into the Waiau River and keep the lake within set levels. The main inflow is the Eglinton River, and the outflow travels south through the Waiau River into Lake Manapouri. The town of Te Anau sits at the southeast corner of the lake. This image was taken from the southern lakefront on 28 October 2025, when the lake was higher than usual and causing local flooding concerns. Lake levels are managed under long-standing rules created after the Save Manapouri Campaign in the 1960s. These rules still guide how the Manapōuri Hydroelectric Power Station operates, even though recent law changes allow more flexible water management without raising the lake beyond its established limits.