Maharajganj is an assembly constituency in Siwan district in the Indian state of Bihar.
As per Delimitation of Parliamentary and Assembly constituencies Order, 2008, No. 112 Maharajganj Assembly constituency is composed of the following: Maharajganj and Bhagwanpur Hat community development blocks.
Maharajganj Assembly constituency is part of No. 19 Maharajganj (Lok Sabha constituency).