Lake Pukaki is the largest of three roughly parallel alpine lakes running north–south along the northern edge of the Mackenzie Basin on New Zealand's South Island. The others are Lakes Tekapo and Ōhau. All three lakes were formed when the terminal moraines of receding glaciers blocked their respective valleys, forming moraine-dammed lakes. The Alps2Ocean mountain bike trail follows the edge of Lake Pukaki for part of its length.
The glacial feed to the lakes gives them a distinctive blue colour, created by glacial flour, the extremely finely ground rock particles from the glaciers. Lake Pukaki covers an area of 178.7 km², and the surface elevation of the lake normally ranges from 518.2 to 532 metres above sea level.
The lake is fed at its northern end by the braided Tasman River, which has its source in the Tasman and Hooker Glaciers, close to Aoraki / Mount Cook. To the west of Lake Pukaki lies the Ben Ohau mountain range with Ben Dhu (1607 m) and Betty Hill (1601 m) closest to the lake. On the eastern side there is some farmland on the flatter contours between Lake Pukaki and Lake Tekapo.
Good views of the taller mountains in Aoraki /Mount Cook National Park, 70 kilometres to the north can be had from the southern shore of the lake.
