Katihar is an assembly constituency in Katihar district in the Indian state of Bihar.

As per Delimitation of Parliamentary and Assembly constituencies Order, 2008, No 63.

Katihar Assembly constituency is composed of the following: Katihar community development block including Katihar nagar parishad; and Hasanganj CD Block.

[1] In 2015 Bihar Legislative Assembly election, Katihar will be one of the 36 seats to have VVPAT enabled electronic voting machines.

[2][3] Katihar Assembly constituency is part of No 11 Katihar (Lok Sabha constituency).