One of the major states of the Indian Union, Bihar is bounded on the north by Nepal, on the east by West Bengal, on the west by Uttar Pradesh and on the south by Jharkhand. Bihar has a number of rivers, the most important of which is the Ganga. The other rivers are the Sone, Poonpoon, Falgu, Karmanasa, Durgawati, Kosi, Gandak, Ghaghara etc.
The history of Bihar is one of the most varied in India. Bihar, the ancient land of Buddha, has witnessed golden period of Indian history. The word “Bihar” has been coined from ”Vihara” meaning Buddhist Monasteries. It is the same land where the seeds of the first republic were sown and which cultivated the first crop of democracy. The state of Bihar is situated in the eastern part of India. It is land-locked on all sides. Bihar is located between the sub-humid Uttar Pradesh in the west and the humid West Bengal in the east. Therefore, it has a transitional climate. Bound in North by Nepal, the home of Himalayas, Bihar emerges from a backdrop of an imposing panorama of eternal snow and Jharkhand in the south. River Ganges flows west to east through the middle of the state, dividing the Bihar plain into two unequal halves. It is located between latitudes 21°-58′-10″ to 27°-31′-15″ N and longitudes 83°-19′-50″ ˜ 88°-17′-40″ E covering a geographical area of 94.2 thousand sq.km. The state stretches to about 483 Kms. from East to West and 345 Kms. from North to South. The average elevation of the state is 173 feet above the sea level. Topographically Bihar can be grouped into three regions: The northern mountainous region, Indo-Gangetic Plain and southern Plateau. The northern mountainous region, Indo-Gangetic Plain and southern Plateau. The Northern mountainous region consists of Someshwar and the Dun hills in the extreme Northwest in Champaran district. These hills are offshoots of the Himalayans system. South of it lies the Tarai region a belt of marshy, swampy, sparsely populated and unhealthy region. The North Gangetic part of Bihar is just south of Tarai. This fertile alluvium tract is the product of various Himalayans and Peninsular rivers like Gandak, Budhi Gandak, Koshi, Mahananda, Bagmati, Gogra and Son and other small river and rivulets. Gangetic plain of Bihar is divided into north and south by Ganga River which is flowing through it. South Bihar Plain has some devegetated hummocky hills which have been subjected to continuous erosion by the rivers flowing through this region. To the further south of Bihar plain lies the plateau region which consists of Kaimur plateau in the west and chhotanagpur plateau in the east. As the Indian sub-continent as a whole is adorned with monsoonal type of climate by the nature Bihar cannot go far away from this general climatic pattern.