N.H. Rev. Stat. Ann. § 202-A:3-a

A public library established or accepted by a town or city shall be deemed a "public agency," and the library trustees a "public body," for purposes of RSA 91-A, and they shall be subject to all applicable provisions of that chapter; provided, however, that any books, documents, records, or other information maintained by a public library that is exempted or protected from disclosure by other provisions of law shall not be subject to disclosure under RSA 91-A.