[3] During the late Vedic period (c. 1100–500 BCE), Videha, along with Kuru and Pañcāla, became one of the major political and cultural centres of South Asia.

[4] The Videha Kingdom was later incorporated into the Vajjika League, which had its capital in the city Vaishali, which is also in Mithila.

In 2006, the Ministry of Panchayati Raj named Supaul as one of the country's 250 most backward districts out of a total of 640.

A dairy farm, which produce approximately 100,000 litres (22,000 imp gal) of milk per day has been established by Bivha Corporation in Simrahi Bazar, Supaul.

[12][13] According to the 2011 census, Supaul district had a population of 2,229,076,[16] roughly equal to the nation Latvia[17] or the US state of New Mexico.

[19] According to the 2011 census, out of the total population of Supaul, 4.74 percent live in urban regions of the district.

The sex ratio in the urban region of Supaul district is 1,000 males to 892 females as per 2011 census data.

As per 2011 census, 2,123,518 people, 95.26% of the population of Supaul district, live in rural areas and villages.

The literacy rate in rural areas of Supaul district is 56.89% as per census data 2011.

NH57 connects Supaul to major cities such as Silchar, Gauhati Siliguri, Forbesganj, Mujjafarpur, Gorakhpur, Lucknow, Ahmedabad and Porbandar.