Siwan

The geographic coordinates of Siwan Assembly constituency are: 26°16'44.4"N 84°20'46.7"E. This constituency falls in Siwan district of Bihar and in the Bhojpur region. Siwan shares its borders with five other Assembly constituencies. Other Bihar Assembly constituencies adjacent to Siwan are: Gopalganj, Barharia, Raghunathpur, Ziradei, Hathua. This constituency shares an inter-state border with .

There were a total of 317805 registered voters on the electoral rolls for the 2025 Assembly election in Siwan Assembly constituency, of which 167679 were male, 150119 female and 7 of the third gender. In the 2020 Assembly elections, there were a total of 311523 registered voters, of which 163489 were male, 148028 female and 6 from the third gender. In the 2015 Assembly elections, there were a total of 280805 registered voters, of which 151835 were male, 128967 female and 185 from the third gender. In 2010 elections, there were a total of 227240 registered voters in this constituency, of which 124943 were male and 102297 female and 96 from the third gender.

The number of service voters in this Assembly constituency was 499 in 2020, 3 in 2015, and 0 in 2010.

The electorate gender ratio (number of female voters per 1000 male voters) in this constituency in 2025 was 895, in 2020 it was 905, 849 in 2015, and 819 in 2010.

Siwan Assembly constituency will go to the polls in Phase 1 of the 2025 Bihar Assembly elections on Thursday, November 6, 2025. The counting of votes is on Friday, November 14, 2025.

In the 2020 state Assembly elections, this seat voted in Phase 2 on Tuesday, November 3, 2020 and the results were declared on Tuesday, November 10, 2020.

In the 2015 state Assembly elections, this seat voted in Phase 4 on Sunday, November 1, 2015 and the results were declared on Sunday, November 8, 2015.

In the 2010 polls, this constituency voted in Phase 3 on Thursday, October 28, 2010 and the results were declared on Wednesday, November 24, 2010.

Assembly constituency no.105. Siwan comprises of the following areas of Siwan district in the Bhojpur region of Bihar: CD Block Siwan; Gram Panchayats Lakri, Pakri, Aurae, Lakri Dargah, Kailgarh Uttar, Kailgarh Dakhin, Sunderpur & Hathigai of Barharia CD Block

This constituency covers an approximate area of 165.24 square kilometers and the geographic coordinates of Siwan is: 26°16'44.4"N 84°20'46.7"E.

A total of five Assembly constituencies in the state of Bihar share borders with Siwan constituency, which are: Gopalganj, Barharia, Raghunathpur, Ziradei, Hathua. This constituency shares an inter-state border with .

According to data released by the Election Commission of India, in the 2025 Bihar Assembly elections, the estimated voter turnout in this Siwan constituency was 59.7%. In 2020, this seat registered a turnout of 54.43%, while it was 56.17% in 2015, and 51.41% in 2010.

In the 2020 Bihar Assembly elections, Awadh Bihari Chaudhary of RJD won in this constituency beating Om Prakash Yadav of BJP by a margin of 1973 votes which was 1.16% of the total votes cast. In 2015, Vyas Deo Prasad of BJP was the winner in this seat beating Bablu Prasad of JDU by a margin of 3534 votes which was 2.24% of the total votes polled in the constituency. In the 2010 Assembly elections, Vyasdeo Prasad of BJP won this seat defeating Awadhvihari Chaudhry of RJD by a margin of 12541 votes which was 10.74% of the total votes polled for the seat.

In the 2020 Bihar Assembly elections, Awadh Bihari Chaudhary of RJD had a vote share of 45.3% in this seat. In the 2015 Assembly elections, Vyas Deo Prasad of BJP got a vote share of 35.02% , In the 2010 Assembly elections, Vyasdeo Prasad of BJP got a vote share of 44.2% in Siwan.