Lake Tekapo is largest of three roughly parallel lakes running north-south along the northern edge of the Mackenzie Basin (the others are Lake Pukaki and Lake Ohau). It covers an area of 83 km2, and is at an altitude of 700 metres above sea level.
The lake is fed at its northern end by the braided Godley River, which has its source in the Southern Alps, to the north.
The lake's outflow is at its southern end, into the Tekapo River. The lake is at the upper end of the Waitaki hydroelectric scheme, and as such, several dams and artificial canals are found near its outflow, linking it with Lake Pukaki.
The lake is a popular tourist destination, and several resort hotels are located at the township of Lake Tekapo at the lake's southern end.
An astronomical observatory is located at Mount John, which is to the north of the town, and south of the small Lake Alexandrina.
