N.H. Rev. Stat. Ann. § 41:65

Any person having an unrecorded document pertaining to the affairs of public importance of any town, parish or division of the state, prior to the year 1825, may submit the same to the secretary of state, with his affidavit of the source from which it was received, and, if it be found to come within such classification, the secretary of state may cause the same to be recorded and indexed with the Ancient Records of Towns, Parishes and other Divisions of the State of New Hampshire, pertaining to such subdivision of the state, and shall record said affidavit therewith, and file the original affidavit in his office.