It is bounded by Uttar Pradesh to the west, Nepal to the north, West Bengal to the east and Jharkhand to the south.
[2] The sub-Himalayan foothills of the Someshwar and Dun mountain ranges in West Champaran district are clad in a belt of moist deciduous forest.
As well as trees, this consists of scrub, grass and reeds.
Here the annual rainfall is above 1,600 mm and this promotes luxuriant sal forests (Shorea robusta) in the favoured areas.
Bihar is one of the states that has taken "considerable" steps to implement the "Scheduled Tribes and Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006".