It is mostly in the Indian state of Rajasthan. It extends into the southern portion of Haryana and Punjab states and into northern Gujarat state. In Pakistan, the desert covers eastern Sindh province and the southeastern portion of Pakistan's Punjab province. In Pakistan's Punjab province it is known as the Cholistan desert. Tharparkar District of province Sindh Pakistan is also a part of Thar desert. The Thar Desert is bounded on the northwest by the Sutlej River, on the east by the Aravalli Range, on the south by the salt marsh known as the Rann of Kachchh (parts of which are sometimes included in the Thar), and on the west by the Indus River.
Its boundary to the large thorny steppe to the north is not well defined. Depending on what areas are included or excluded, the nominal size of the Thar can vary.