Bistcho Lake has a total area of 413km2 (159sqmi) (with 13km2 (5.0sqmi) islands area and 413km2 (159sqmi) water surface), and lies at an elevation of 552m (1,811ft). It is the third largest lake in Alberta (or fourth if considering Lake Athabasca, which is partly in Saskatchewan).
Bistcho Lake is located in the hydrographic basin of the Liard River, to which it is connected by the Petitot River. The waters of the lake drain to the Arctic Ocean through the Petitot, Liard and Mackenzie River.