The Kalinga War was fought in ancient India between the Maurya Empire under Ashoka and the state of Kalinga, an independent feudal kingdom located on the east coast, in the present-day state of Odisha and northern parts of Andhra Pradesh. It is presumed that the battle was fought on Dhauli hills in Dhauli which is situated on the banks of Daya River. The Kalinga War was one of the largest and deadliest battles in Indian history. Kalinga did not have a king as it was culturally run without one.
This is the only major war Ashoka fought after his accession to the throne. In fact, this war marks the close of empire-building and military conquests of ancient India that began with the Mauryan king Bindusara. In the entire Indian history this war is considered as the deadliest war costing nearly 250,000 lives.