Dimna Lake is an artificial reservoir located near Dalma Wildlife Sanctuary, 15 km from the city of Jamshedpur, in the state of Jharkhand, India.

Dimna Lake covers about 5.5 km2, around 1,861 acres were acquired under the Land Acquisition Act of 1894 for the dam.

The harvested rainwater majorly supports local community, biodiversity and municipal water demand of Jamshedpur town during monsoon season.

Nature had provided a readymade basin and a range of hills in such a manner that by closing two small gaps, a large quantity of water could be stored.

In the late 1930s, Jamshedpur felt that water scarcity could hit the people of the city as the population was growing rapidly.