Lake Maraetai is one of several artificial lakes formed as part of a hydroelectricity scheme on the Waikato River in the North Island of New Zealand. It is located 85 km southeast of Hamilton, close to the town of Mangakino. It is a relatively small lake, covering only 4.4 km2, but it is 75 m deep at some points, and the powerhouses (Maraetai I and Maraetai II) at its northern end generate 360 MW of power.