Lake Coleridge (Māori: Whakamatau) is located in inland Canterbury, in New Zealand's South Island. Located 35 kilometres (22 mi) to the northwest of Methven, it has a surface area of 47 square kilometres (18 sq mi). The lake is situated in an over-deepened valley formed by a glacier over 20,000 years ago in the Pleistocene era. It currently has no natural outflows. There is a small settlement at the lake.