Purnia has an area of 3,202 square km. It is a level, depressed tract of country, consisting for the most part of a rich, loamy soil of alluvial formation. It is traversed by several rivers flowing from the Himalayas, which afford great advantages of irrigation and water-carriage. Its major rivers are the Kosi, the Mahananda, the Suwara Kali and the Koli. In the west the soil is thickly covered with sand deposited by changes in the course of the Kosi. Among other rivers are the Mahananda and the Panar. Its major agricultural products are jute and banana.