An impact crater lake is a lake inside a depression caused by the impact of a meteor. It is also known as an annular lake in cases where the water body is shaped like a ring, as many impact crater lakes are.
One of the largest impact crater lakes is Lake Manicouagan in Canada; the crater is a multiple-ring structure about 100 km (60 mi) across, with its 70 km (40 mi) diameter inner ring its most prominent feature; it contains a 70 km (40 mi) diameter annular lake, surrounding an inner island plateau, René-Levasseur Island. It is Earth's sixth-largest confirmed impact crater according to rim-to-rim diameter.[1]