What is the deepest freshwater lake on Earth?

The deepest freshwater lake on Earth is Lake Baikal.

Located in southern Siberia, Russia, Baikal reaches a maximum depth of 1,642 metres. It is also the world’s oldest existing lake, estimated to be about 25–30 million years old, and it formed in an active continental rift where Earth’s crust is pulling apart.

Baikal holds roughly 22–23% of the planet’s unfrozen surface freshwater—more than all of North America’s Great Lakes combined. That makes it the largest freshwater lake by volume, although it is only the world’s seventh-largest lake by surface area.

A common mix-up is the Caspian Sea, which is larger by surface area but is generally classified as a saline inland sea. Baikal is also famous for its unusual wildlife, including the endemic Baikal seal and several species of deep-water fish. UNESCO designated the lake a World Heritage Site in 1996.