Jamui has a past that makes it an important part of the history of Bihar state. Its past stretches back into the age of the Mahabharata wars. There is sufficient archaeological and historical evidence to prove that there is a close association with the Jain tradition from its inception till present day times. There are mainly two theories put forward by historians regarding the origin of the name of the district Jamui. The first supposes that the name of Jamui was derived from “Jambhiya Gram” or “Jribhikgram” village, which has the fame of possessing the place where Mahavira attained ‘Omniscience’ or Kevalaygnan. Another theory maintains that the name Jamui originated from Jambuwani. As per the study of some historians the place of Jamui, was very famous in the era of the Mahabharata. According to the available historical documents, this region was closely associated to Gupta and Pala rulers prior to the 12th century. But soon after that it came under the control of the Chandel rulers. Before the Chandel Raj, this place was a part of the Nigoria Empire whereas Nigoria was defeated in the hands of Chandels, founded in the 13th Century. At that time the kingdom of Chandels spread over the entire Jamui. The district of Jamui came into existence in the year 1999.

Chandrashekhar Singh, an eminent Indian politician and the Chief Minister of Bihar from August, 1983 to March, 1985 was born on 17th August, 1927 at Malaypur in the Jamui district. He also held a number of Cabinet Minister Positions in the Cabinet of Indira Gandhi and Rajiv Gandhi. He was a member of Indian National Congress party.

Geographically, the district lies at 24°92'N latitude, 86°22'E longitude and 78 m Altitude. In the year 2021, there was a total 21.34% forest area of total geographical area. The district encompasses a geographical area of 2,494 sq km. and it is bounded by Lakhisarai district on the north, Munger district on the north east, Sheikhpura district and Nawada district on the north west, Banka district on the east and Jharkhand on the south and south west. During the summer, the climate of the district remains extremely hot. Most of its rainfall occurs in the monsoon season. The actual rainfall in the district was 1228.1 mm in the year of 2021-22.

Administration wise, the district is divided into 1 sub-division namely Jamui. There are 1 Lok Sabha seat and 4 Assembly constituencies in the district. Moreover, the district comprises 5 towns and 1,503 villages. The administrative language in the district is Hindi.

According to 2011 census the population in the district is 17,60,405 including 9,16,064 are males and 8,44,341 are females. The district has a sex ratio of 922 females for 1000 males. In the year 2001-2011 the population growth rate in the district was 25.85% out of which 25.64% were males and 26.09% were females. As per 2011 census the major religion in the district is Hindu and Muslim with 86.67% and 12.36% of the total population. The population density in the district is 706 persons per sq. km. According to 2011 census the principal language in the district is Hindi with 89.43%. In the year 2020 the number of live births in the district was 57,413 out of which 29,471 were males and 27,938 were females. In the same year the number of deaths in the district was 6,021 out of which 3,726 were males and 2,295 were females.

The economy of the district is mainly based on agriculture. Almost all people of the district is engaged in agriculture since it has no big industries and factories. Every year a huge chunk of revenue comes from the agricultural products grows in the district. Some of its chief agricultural products are paddy, wheat, lentils, etc. In 2006 the Ministry of Panchayati Raj declared Jamui as one of the country's 250 most backward districts and currently receiving funds from the Backward Regions Grant Fund Programme (BRGF). In the year 2011-12 the gross domestic product in the district was Rs. 2,89,818 lakh at current price and Rs. 1,73,912 lakh at constant prices in the year 2004-2005. In the year 2011-12 the net domestic product in the district was Rs. 2,57,159 lakh at current price and Rs. 1,51,772 lakh at constant prices in the year 2004-2005.

The district is not very developed educationally. Lack of educational institutions in the district compels its students to go to other places in order to take education. As per 2011 census the literacy rate in the district is 59.79% including 71.24% are males and 47.28% are females. The number of literates in the district is 8,58,588 out of which 5,34,385 are males and 3,24,203 are females.

Digvijay Singh, a distinguished Indian politician and a Member of the Parliament for five times i.e. three times in the Lok Sabha (1998, 1999 and 2009) and two times in the Rajya Sabha (1990, 2004) was born on 14th November, 1955 at Gidhaur in the district. Giridhari Yadav, an illustrious Indian politician and currently a member of the Legislative Assembly of Bihar was born on 14th April, 1961 at Jamui town. He is a member of the Janata Dal (United) (JDU) political party.

The district has some tourist spots which allures numerous travellers from different parts of the country. The Kali Mandir situated at Malaypur village in the district attracts pilgrims from across the country. Moreover, the Kali mela held in this place every year is very famous. Jain Mandir Dharamsala in the district is especially for the jain pilgrims. The Mahavira temple within the Dharamsala is its identity. Giddheshwar temple in the district is the temple of Lord Shiva situated on the top of stone boulders. Minto tower, constructed by Maharaja Rameshwar Prasad Singh of Giddhour was built in the commemoration of Lord Minto who had served as the Viceroy and Governor General of India. Some other notable centres of attraction in the district are Kshatriya Kund Gram, Kankan, Indpai, Kumar Gram, Simultalla, Lachhuar Jain temple, etc.