Atansor (Kazakh: Атансор) is a salt lake in Birzhan sal District, Akmola Region, Kazakhstan.

[2][1] Atansor is an endorheic lake of the northern end of the Kazakh Uplands.

It has an irregular shape, with wide bays in the north and in the south of the eastern part.

[2][3] About 30% of the land surface surrounding the lake consists in plowed agricultural fields.

The remaining is used for livestock grazing and is covered with steppe vegetation, where sagebrush, needlegrass, and fescue predominate.