History of Kaimur District in Bihar is old and interesting. In pre-historic days, the plateau region of the district has been the abode of the aboriginals whose chief representatives now are Bhar, Chero tribe and the Savers. According to some legends, Kharwar Tribes were the original settlers in the hilly tracts of Rohtas District. The Oraon Tribe also claim that they ruled over the stretch falling between Rohtas and Patna. One local legend also connects Sasaram the present headquarters of Rohtas with king Sahasrarjun, who was killed by Saint Parshurama in a fight.

Early History of Kaimur District
According to the history of Kaimur District, this district formed part of Magadha Empire until 5th century AD, under the Maurya Empire and Gupta rulers of Magadha. In 7th century AD, Kaimur District came under the control of Harshavardhana, the ruler of Kannauj. An inscription in the Mundeshwari temple near Bhabua refers to the king Uday Sena as the ruling chief of the area. The area of this district successively came under the rulers of Shail dynasty of central India and Pala dynasty of Bengal.

Medieval History of Kaimur District
According to some Indian historians, the first ruler of Pala dynasty, Gopala controlled this region. Later on Chandauli controlled Varanasi-Chandawali and Kaimur District in the 12th century AD, as confirmed by the Tarachandi inscription near Sasaram. After the decline of the Gupta Empire, the district in all probability relapsed into the hands of the aboriginal tribes and came under the control of petty chieftains. The Rajputs who came from Ujjain and the province of Malwa Plateau had a series of conflicts with the aboriginals and it took them many hundred years to subdue the aboriginal completely. The Census report of 1961 describes that when Bakhtiar Khiliji attacked Bihar in 1193 AD, he found Shahabad in the hands of some Rajput chiefs often fighting among themselves. They were not united and strong enough to offer powerful resistance to the Muslim invaders. Hence, Bakhtiyar Khiliji had an easy victory over them and the district soon became a part of his kingdom. Later it was annexed, along with the rest of Bihar, to the kingdom of Jaunpur. A hundred year later, it passed under the direct control of Muslim empire of Delhi. In 1537, old Shahabad District witnessed advancement of Humayun and his subsequent conflict with Sher Shah Suri at Chausa known as Battle of Chausa. Later the district of Shahabad (which included Kaimur district also) was included in Akbar`s empire.

Modern History of Kaimur District
In 1764, old Shahabad district witnessed conflict for supremacy and the British rulers took over the area after defeating Mir Qasim, in the battle of Buxar. Lastly, the historic Sepoy mutiny had its impact in the district. Much after independence, in the year 1972 Rohtas District was formed out of the old Shahabad District and in the year 1991 Kaimur District was formed out of Rohtas District.