Kishanganj was the old and important sub-division of Purnia district. After a hard struggle of 17 years, the Kishanganj District came into existence on 14th January 1990. It is situated in the north–east of the State of Bihar, bordering areas of West Bengal, Nepal and Bangladesh. The district headquarter is 425 kms away from the State capital Patna. The district has one sub-division: Kishanganj and seven blocks: Kishanganj, Pothia, Kochadhamin, Thakurganj, Bahadurganj, Dighalbank, Terhagachh. It has two Nagar Panchayats: Bahadurganj and Kishanganj; and one municipality, namely Kishanganj. The total number of Gram Panchayats and revenue villages in the district is 126 and 802 respectively. It has one parliamentary constituency (Kishanganj) and three assembly constituencies (Kishanganj, Thakurganj and Bahadurganj). Kishanganj district occupies an area of 1,884 square kilometres (727 sq mi), Kishanganj district is surrounded by Araria district in the west, Purnia district in the south-west, Uttar Dinajpur district of West Bengal on the east, and Darjeeling district of West Bengal andNepal on the north.
A narrow strip of West Bengal, about 20 km wide separates it fromBangladesh Kishanganj district is located between 250 20’ and 260 30’ north latitudes, and 870 7’ and 880 19’ east longitudes. Major rivers flowing through the district are Mahananda, Kankai, Mechi, Donk, Ratua and Ramzan Sudhani. In 2006 the Ministry of Panchayati Raj named Kishanganj one of the country's 250 most backward districts (out of a total of 640). It is one of the 36 districts in Bihar currently receiving funds from the Backward Regions Grant Fund Programme (BRGF). The district comprises only one sub-division, Kishanganj, which is further divided into seven blocks: Bhahadurganj, Dighalbank, Kishanganj, Kochadhaman, Pothia, Terhagachha, Thakurgunj According to the 2011 census Kishanganj district has a population of 1,690,948, This gives it a ranking of 293rd in India (out of a total of 640). The district has a population density of 898 inhabitants per square kilometre (2,330 /sq mi) . Its population growth rate over the decade 2001-2011 was 30.44%. Kishanganj has a sex ratio of 946 females for every 1,000 males, and a literacy rate of 57.04%.
A vast majority of the people live in the villages. A predominantly Muslim area, with Muslims forming about 70 per cent of the population, there are also Hindus of whom Surajpuris and other backward castes predominate. There also are small Santal pockets. The inhabitants of Kishanganj mostly speak Surajpuri, one of the Rajbongshi languages which has much similarities withBengali. Kishanganj district had a literacy rate of 31.02 per cent in 2001, the lowest amongst all the districts of Bihar. The literacy rate of Bihar at 47.53 per cent is amongst the lowest in India, which has a literacy rate of 64.84 per cent. While the male literacy rate in Kishanganj district stood at 42.8 per cent, female literacy at 18.49 per cent was the lowest in India.
The NH-31 passes through this district, which acts as a corridor to the whole north-east provinces. Besides this, there are state highways, which connect the different villages and towns. There is a good rail link from Kishanganj to other states of India. It has both the meter and broad gauge railway line. Surjapuri is the main language (local dialect) of this district. Apart from this, Hindi, Urdu and Bengali are also spoken.