The Siwan constituency of the Lok Sabha is encompassed in the administrative district of Siwan of the state of Bihar. The constituency is assigned the number 18 of the 40 Lok Sabha constituencies of the state of Bihar by the Election Commission of India.
The Siwan parliamentary constituency is part of the administrative district of Siwan within the state of Bihar and is designated as one of the 40 Lok Sabha constituencies in the state, according to the Election Commission of India.