The famous Didwana salt water lake is located in the Nagaur district of Rajasthan.
The lake is about 4 km long and 3 km wide, surrounded on all sides by sand hills except west.
In addition to salt production, sodium sulphate is also produced from the Diwane lakes.
It is the second most important and largest lake in Rajasthan after Sambhar Lake which covers an area of 10 sq. kilometers.
Didwana was a major trading center of the medieval Mughal Empire due to its famous salt lakes.
There were several battles between the emperor of Gujarat and the rulers of Jodhpur, Bikaner and Jaipur over the rights of this lake.
Maharana Kumbh of Chittorgarh levied a tax on salt, which is mentioned in the Kirti Pillar inscription.
Isolated hills of graphitic phyllite and quartzite are seen on the western side of the lake.
The presence of uranium is found in the playa sediments of Didwana Lake.