N.H. Rev. Stat. Ann. § 14:29

If a person shall attend a session of the legislature and vote therein as a representative from any town or city, knowing that, by reason of want of the requisite number of inhabitants in said town or in the ward of the city which he represents, he is not lawfully entitled to a seat in the house of representatives, or that he was not legally elected a representative of such town or ward, he shall be guilty of a class B felony.