The lake is 25 kilometres (16 mi) long, following north-south geological structures, but is narrow like a river.

The lake surface is about 330 metres (1,080 ft) above sea level.

[2] Granitoid ridges near the lake rise to about 410 metres (1,350 ft) above sea level.

[1] Most of the region is underlain by granodiorite to tonalite gneisses, which are exposed on the shores of the central portion of the lake.

The warmest month is July, when the average temperature is 17 °C (63 °F) and the coldest is January, with −21 °C (−6 °F).