Purnia is a city that serves as the administrative headquarters of both Purnia district and Purnia division in the Indian state of Bihar.

 It is the largest city in northeastern Bihar. It is nearly 300 kilometres from Patna, the capital of Bihar, as well as 171 km from Siliguri, 92 km from Bhagalpur, and 214 km from Muzaffarpur. It is 450 km from Kolkata, the capital of the adjacent state of West Bengal and the largest city in East India.

The Indian Army, Indian Air Force, and three of five branches of India's Central Armed Police Forces – the Border Security Force (BSF), the Sashastra Seema Bal (SSB), and the Indo-Tibetan Border Police (ITBP) – have bases around the district.

The origin of the name appears to have different sources. The name may originate from the Sanskrit word Purna–Aranya, which stands for "complete jungle". Purnia could be an altered form of the old name Purania, derived from the word purain or Lotus, which is said to have grown on the Kosi and Mahananda rivers.

The modern district of Purnia was formed by the East India Company on 14 February 1770, making it one of the oldest constituted districts in India.

Best time to visit the destination October to April