Mass. Gen. Laws ch. 102 § 4
For the purposes of sections one, two and three, the outer limits of Boston harbor shall be a line drawn from Harding's Rock to the Outer Graves and thence to Nahant Head, and said harbor shall include the shores of Chelsea; the outer limits of Salem harbor shall be the chops of said harbor; the harbor of Fall River shall include the waters of Taunton Great river and Mount Hope bay, from the south line of the town of Freetown to the Rhode Island state line, including the shores of Somerset; the harbors of New Bedford and Fairhaven shall be considered one harbor, the outer limits of which shall be the outer limits of Buzzard's bay; and the outer limits of Gloucester harbor shall be a line drawn from Eastern Point to Norman's Woe.
Mass. Gen. Laws ch. 102, § 4