The Mahanadi River is a major river in East Central India. It drains an area of around 132,100 square kilometres (51,000 sq mi) and has a total length of 900 kilometres (560 mi). Mahanadi is also known for the Hirakud Dam which was the first major multipurpose river valley project after India's independence in 1947. The river flows through the states of Chhattisgarh and Odisha and before finally ending in the Bay of Bengal.

Hirakud Dam is built across the Mahanadi River, about 10 kilometres (6.2 mi) from Sambalpur in the state of Odisha in India. It is the longest earthen dam in the world. Behind the dam extends a lake, Hirakud Reservoir, 55 km (34 mi) long. It is one of the first major multipurpose river valley projects started after India's independence. Hirakud Reservoir was declared a Ramsar site on 12 October 2021.