Purnea has a rich history and a glorious past. It is believed that the name Purnea originates either from the Goddess Puran Devi (Kali) or from Purain meaning Lotus.
The earliest inhabitants of Purnea were Anas and Pundras. In the epics, the Anas are grouped with the Bengal tribes and were the eastern most tribes known to the Aryans during the period of Atharva Samhita while the Pundras, although they had Aryan blood were regarded as degraded class of people in the Aitarya Brahmana, Mahabharata and Manu Samhita, because they neglected the performance of sacred rites.According to the legend of Mahabharata, Biratnagar which gave shelter to the five Pandava brothers during their one year incognito exile, is said to be located in Purnea.
During the Mughal rule, Purnea was a military frontier province under the command of a Faujdar. The revenue from this outlying province was spent on the maintenance of troops for protecting the borders against tribes from the north and east. According to Ain-i-Akbari, Purnea was a Sarkar within the Subah of Bengal.Purnea became a possession of East India Company in 1765 and was formed as a district on 10th February 1770. Rambagh was a famous European settlement while Sarsi was a famous indigo centre under the Europeans.Swadeshi movement and Kissan Sabha movement figured prominently in Purnea district during the early 20th century.