N.H. Rev. Stat. § 484:8
The said agreement or compact, when ratified by the legislature of each of said states and approved by the Congress of the United States, shall thereupon become operative and effective. The governor is authorized and directed forthwith to notify the governor of the Commonwealth of Massachusetts and the President of the United States that the state of New Hampshire on its part has approved and ratified said compact or agreement. Upon its execution in triplicate by the commissioners or representatives of each of said states as aforesaid, a duly executed original of the compact shall be filed in the office of the secretary of state of New Hampshire, together with the original notice of ratification received from the governor of Massachusetts, and such notice, if any, as may be received from the President or the Congress of the United States, signifying the approval of such Congress to the compact.
RSA 484:8
1989, 339:1, eff. Jan. 1, 1990.