N.H. Rev. Stat. § 14:9-a

I. Except as provided in paragraphs II and III, and except for resolutions, which shall take effect upon their passage, each law passed by the general court shall take effect 60 calendar days following passage, excluding the date on which it is signed by the governor, or the last date on which the general court acts on the matter, as the case may be. II. The office of legislative services shall include a section in each bill drafted for introduction specifying the act's effective date, if passed. The effective date section shall indicate that the law shall take effect as follows or at such other time as the bill's prime sponsor shall indicate in writing: (a) Each law affecting judicial practice and procedure, or establishing or eliminating criminal prohibitions, civil causes of action or remedies, or limitations of actions, shall take effect on the January 1 following passage. (b) Each law affecting local property taxes shall take effect on the April 1 following passage. (c) Each law affecting state tax laws and statutory fees shall take effect on the July 1 following passage. (d) If the law affects only one particular person, town, city, or political subdivision, it shall take effect upon its passage. (e) Each law making appropriations shall take effect on the July 1 following passage. (f) Each law establishing a legislative committee shall take effect upon its passage. (g) All other laws shall take effect 60 days after the bill's passage. III. A law may be repealed in the bill enacting the law, with the repeal taking effect at a prospective date specified in the bill. IV. The office of legislative services shall, at the request of the sponsor of an amendment, include in the amendment the effective date requested by the sponsor of the amendment. V. Unless specifically provided otherwise, each law enacted by the general court shall take effect at midnight, 12:00 a.m., on the date the law becomes effective. VI. The secretary of state shall record the date each law was enacted and its effective date on all enrolled and printed copies of such law, and such record shall be conclusive.