Mass. Gen. Laws ch. 1 § 7A
The governor, if he finds that the public interest will benefit thereby, may accept on behalf of the commonwealth retrocession of all or part of the legislative jurisdiction over property within the commonwealth over which such jurisdiction has been ceded to the United States by the commonwealth. Such acceptance of retrocession shall take effect in each case upon the written acceptance by the governor of a notice of retrocession signed by the duly authorized officer or agent of the United States having supervision and control over the property being retroceded. A copy of the notice of retrocession and the written acceptance thereof shall be filed with the state secretary and the city or town clerk of the city or town in which the affected property is located, and in the case of property located in more than one city or town, with the clerk of each municipality in which the property is located.
Mass. Gen. Laws ch. 1, § 7A