Mass. Gen. Laws ch. 52 § 2
Each political party shall, in every ward and town, elect at the presidential primaries a ward or town committee from among the members of the party who either have enrolled on or before the ninetieth day prior to the last day for filing nomination papers for such committees with the state secretary, or are newly registered voters in their city or town enrolled in that political party and have not been enrolled in another political party during the year preceding such last day for filing nomination papers. Ward and town committee members shall hold office for a period of four years ending on the thirtieth day following the day on which the presidential primaries are next held and until their successors shall have organized. If any member changes his residence from the ward or town in which he was elected during the said four years, he shall cease to be a member at the end of the calendar year during which said residence is changed. If any member, whether elected or chosen to fill a vacancy, cancels or changes his party enrolment he shall forthwith cease to be a member of said committee.
For the purposes of this chapter, notwithstanding the fact that ward lines in a city have been redistricted subsequent to a presidential primary, members of ward committees elected from wards in existence at the time of a presidential primary shall continue to represent said wards until their successors shall have been elected and organized under the redistricted ward lines at the presidential primary next following said redistricting.
Mass. Gen. Laws ch. 52, § 2