The lake lies at the altitude 420 m, is 105 km long and 22-48 km wide, with the maximum depth 15 m. Its major tributaries are the Kara-Irtysh (Black Irtysh) and Kendyrlyk from the east, its only outlet is the Irtysh River (or White Irtysh).
It abounds in fish. The lake is generally frozen from the beginning of November to the end of April. Since the construction of the Bukhtarma dam the lake has risen 6 m (20 ft) above its natural level.