[1] It is the 30th largest lake in the world by area, and the world's largest lake on an island, with an area of 5,542 km2 (2,140 sq mi) and a maximum length of 123 km (76 mi).

[4] The lake is in the Great Plain of the Koukdjuak about 280 km (170 mi) northwest of Iqaluit.

The lake's name is of Inuktitut origin, coming from the word for the adult ringed seal (netsilak).

It empties west via the very shallow Koukdjuak River into Foxe Basin.

Ringed seals live in the lake, along with three recorded species of fish: the Arctic char, the ninespine, and three-spined stickleback.