Ulken Tobylzhan (Kazakh: Үлкен Тобылжан; Russian: Большой Таволжан, Bolshoy Tavolzhan) is a salt lake in Uspen District, Pavlodar Region, Kazakhstan.

Part of the salt is exported to the Western Siberia region.

The group of lakes is flat and has a diameter of roughly 18 kilometers (11 mi).

[3] Located in the southern half, Ulken Tobylzhan is the largest of the lakes in the cluster.

There are a number of smaller lakes, as well as salt marshes in the Tobylzhan cluster.