N.H. Rev. Stat. Ann. § 655:28

A candidate for nomination for the office of governor, councilor, state senator or state representative shall swear an affidavit covering his qualifications as to age, that the candidate is a registered voter, that his domicile is in the district he desires to represent, that he is not a candidate for incompatible offices as defined in RSA 655:10, and that he is not a federal employee which he understands would make him ineligible to file his candidacy. The secretary of state shall not print upon the primary ballot of any party the name of any person unless there is filed with him such an affidavit at the time his candidacy is filed. If the candidate files in person before a town clerk or a deputy town clerk, such clerk shall be empowered to witness the affidavit whether or not that clerk is a notary public.