Consists of the following towns:

Acton, Bedford, Belmont, Boston (Ward 5 - Precincts 3-9; Ward 21 - Precincts 3-16; Ward 22), Brookline, Cambridge, Carlisle, Concord, Lincoln, Littleton, Maynard, Natick, Newton, Stow, Sudbury, Waltham, Watertown, Wayland, Wellesley, Weston.