Ujiarpur constituency is one of the 243 legislative assembly constituencies of Bihar, it is located in the Samastipur district . The current MLA from this constituency is Alok Kumar Mehta of the Rashtriya Janata Dal (RJD) who secured 90,601 in the 2020 general elections, beating Sheel Kumar Roy of the Bharatiya Janata Party (BJP) by a margin of 23,268 votes.

In the 2020 general election the total number of electors registered in this constituency was 299,159 where the male electors amounted to 159,709, female electors amounted to 139,444 and 6 electors belonged to the third gender. Out of the total registered electors 185,735 electors cast their votes marking the voter turnout at 62.09%

The recent data from 2024 by the election commission shows that there are 306,236 total registered electors in Samatipur constituency in which 161,905 electors are male, 144,328 electors are female and 3 electors are of the third gender. Polling for this constituency will take place in the first phase of elections on 6th November 2025.

Ujiarpur falls in the Mithila region and this region has a very rich and vibrant culture with many folk songs, dance forms, and traditional art. The Mithila paintings, commonly known as Madhubani paintings is an art form that is appreciated and respected globally.

This constituency covers an approximate land area of 218.33 square kilometers. Ujiarpur shares its borders with four other legislative assembly constituencies of Bihar which are Samastipur, Warisnagar, Bibhutipur and Sarairanjan.