The Great Indian Desert lies to the South-west of the fertile Northern Plain or the Gangetic Plain. It is also called the Thar Desert. The Aravali Hills divide Rajasthan into two parts. The Western part of Rajasthan is the Great Indian Desert. Its soil is composed of sand, hard rocks and sand dunes.
In the given map you find that the Great Indian Desert extends from the Aravalis in the East to Pakistan in the West. It touches the boundaries of Punjab and Haryana in the North and the Northeast and Runn of Kutch in Gujarat in the South. Actually the Indian Desert is a part of a very big desert. The Thar Desert which extends to Sindh in Pakistan and beyond Pakistan to Arabia.
The Great Indian Desert is a vast stretch of sand and sand dunes which is about 500 km. long and 200 to 250 km. wide. Sand dunes are mounds piled up of sand. The strong winds carry away these dunes to other places and they keep on changing their places.