It is the oldest district in the state of Bihar. In 1912, Bihar and Orissa were carved as separate provinces out of the old Bengal Province and Purnea became the district of the new provincial unit. Before the state re-organization in 1956, Purnea was contiguous to East Pakistan. The area of this district was about 4,239 square miles (10,979 km²). Buchanan Hamilton the first historian-geographer of India visited Purnea in 1801-10.
Nurtured by The Kosi, pampered by the mellifluous Mahananda, showered gracefully by Lord Indra, abuzz with sweet Maithili and portrayed beautifully by Renu, Purnea, no doubt, qualifies itself to be called Mini Darjeeling. Actually Purnea originate from the Pundra Kingdom (also known as Paundra, Paundraya, Purnea etc). This was an eastern kingdom located in Eastern Bihar, West Bengal and Bangladesh. The bhats of the Pundir Rajputs, state that, having had their origins in Telangana, the Pundirs are descendants of the great Pundra dynasty. A Pundra king challenged Vasudeva Krishna by imitating his attributes. He called himself Paundraka Vasudeva. He was later killed by Vasudeva Krishna in a battle. The founders of five eastern kingdoms, which included: - Angas Vangas, Kalingas, Pundras and Suhmas shared a common ancestry. The name Purnea is an altered form of the old name Purania. This name as stated in the locality has been derived from the word purain that means the Lotus, the local plant, which is said to have grown thickly on the beds of the river Kosi and Mahananda, where swamps and marshes have been formed. This derivation has been ascertained by O'Malley also in the old gazetteer.