Bihar is one of the important Eastern states of India. It lies between 25°8′ & 27°31′ North Latitude and 83°20′ & 88°17′ East Longitude occupying an area of 94,163 sq. km. State’s average elevation is 173 feet above the sea level.
Nepal lies on North and on other sides it shares the border with Jharkhand (South), West Bengal (East) and Uttar Pradesh (West). It can be grouped into three regions, topographically : The northern mountainous region, Indo-Gangetic Plain and southern Plateau.
Northern mountainous region consists of Someshwar and the Dun hills in the extreme Northwest in Champarn 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.
Bihar’s 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.
Bihar’s Gangetic plain is divided into north and south by Ganga river which is flowing through it. Bihar’s South Plain has some devegetated hummocky hills which have been subjected to continuous erosion by the rivers flowing through this region. Bihar’s south plain lies the plateau region , which consists of Kaimur plateau in the west and Chhotanagpur plateau in the east.
Bihar is located between 25 to 27 degree North latitude and the climate of the state is of mostly sub-tropical. It is close to Tropic of Cancer , and during summer it experiences tropical climate. Bihar has hot summer season during months of March to May. The average temperature is 35-40 Celsius throughout the summer . April and June are the hottest months of the year.
Because of its location is Northern hemisphere, December to January is the winter season in Bihar. The winter in Bihar is mild with average temperature being 5 to 10 degree Celsius. Bihar gets its maximum rainfall during South-West monsoon season during the months of June to September. The average rainfall of Bihar is around 120 cm.
Bihar lies in t between the wet climate of West Bengal and North-Eastern Provinces ; Semi arid climate of Western Uttar Pradesh. Bihar’s natural vegetation is moist deciduous forests. These forests are mostly found in northern and southern parts of the state. Bihar has three types of soil: montane, alluvium and marshy/swampy soil of Tarai.
According to 2001 Census, Bihar has a total population of 8.29 crores with an average density of 880 persons per sq. km. In Bihar , rural population constitutes the 90% of the total population. More than half of the people (58%) are below 25 years . Majority of the population (83%) are the followers of Hinduism and Islam is practised by 17% of the people.