N.H. Rev. Stat. § 1:15

Until otherwise established by law, interstate compact or judgment of the supreme court of the United States, the lateral marine boundaries of this state shall be and are hereby fixed as follows: I. Adjoining the State of Maine: Beginning at the midpoint of the mouth of the Piscataqua River; thence southeasterly in a straight line to the midpoint of the mouth of Gosport Harbor of the Isles of Shoals; thence following the center of said harbor easterly and southeasterly and crossing the middle of the breakwater between Cedar Island and Star Island on a course perpendicular thereto, and extending on the last-mentioned course to the line of mean low water; thence 102degree East (true) to the outward limits of state jurisdiction as defined in RSA 1:14. As to that section of the lateral marine boundary lying between the mouth of the Piscataqua River and the mouth of Gosport Harbor in the Isles of Shoals, the so-called line of "lights on range", namely, a straight line projection south-easterly to the Isles of Shoals of a straight line connecting Fort Point Light and Whaleback Light shall be prima facie the lateral marine boundary for the guidance of fishermen in the waters lying between Whaleback Light and the Isles of Shoals. II. Adjoining the Commonwealth of Massachusetts: As defined in chapter 115, 1901; and thence one hundred and seven degrees East (true) to the outward limits of state jurisdiction, as defined in RSA 1:14. III. The fixation of lateral marine boundaries herein is without prejudice to the rights of this state to other marine territory shown to belong to it. By the fixation of the foregoing lateral marine boundaries, this state intends to assert title to its just and proportional share of the natural resources in the Atlantic Ocean lying offshore its coastline and within the limits defined in RSA 1:14.