The Great Lakes Depression (Mongolian: Их нууруудын хотгор, Ikh Nuuruudyn Khotgor), also called the Great Lakes' Hollow is a large semi-arid depression in Mongolia that covers parts of the Uvs, Khovd, Bayan-Ölgii, Zavkhan and Govi-Altai aimags. Bounded by the Altai in the West, Khangai in the East and Tannu-Ola Mountains in the North, it covers the area of over 100,000 km2 (39,000 sq mi) with elevations from 750 to 2,000 m (2,460–6,560 ft).
Small northern parts of the depression are part of Russia.
The depression is named so because it contains six major Mongolian lakes: saline Uvs Nuur, Khyargas Nuur and Dörgön Nuur; and freshwater Khar-Us Nuur, Khar Nuur and Airag Nuur. In addition, it includes 14,000 km2 (5,400 sq mi) of solonchaks and large sandy areas. Northern parts are dominated by arid steppes, and southern by semideserts or deserts. The major rivers are Khovd River, Zavkhan Gol, and Tesiin Gol.