People believe that the name Hardoi comes from distorted version of its earlier name Haridrohi, which is a Hindi word that means "anti to the God". According to Hindu theology, in the past it was ruled by a king Hirnakashyap, who didn’t have faith in God, but instead declared himself as God. He wanted the people to pray to him, but later his own son Prahlad rebelled. He tried to kill his own son by various means, but was unsuccessful. Later, to save Prahlad, God himself came in disguise, such that he was neither human nor animal, and killed "Hirnakashyap". According to some scholars, the term "Hardoi" originated from the term "Haridwaya" which means two gods. Since there were two gods, Baman bhagvan (in the regime of King Bali) and Narsimha Bhagvan (in the regime of King Hiranyakashipu) had been incarnated hence the place called Haridwaya and later called Hardoi.
Hardoi is first mentioned during the Muslim rule. In 1028, Bwan was invaded by Sayyid Salara Masgud. However, Muslims didn’t occupy the region until 1217. Many battles between the Mogul and Afghan empires took place in Hardoi district due to the situation of the district. Humayun was defeated by Sher Shah Suri between the cities of Bilgram andSandi, and he escaped by crossing the river Ganges with the help of a bhisti to whom he had made the king for one day after regaining the throne.
Later, in February 1856, Hardoi, as a part of Oudh, became part of the British territory after Lord Dalhousie's proclamation. The headquarters of the district were at first Mallawan, but then became Hardoi after the Sepoy Mutiny.
Hardoi is a place where we have a many old temples which are world famous, such as Neemsaar, Sarvan Devi and BabaMandir