CT line at Dudley to NH line at Winchendon via Oxford, Worcester, Leominster and Fitchburg.

Brief multiplex with US 202 in Winchendon.
Multiplexed with MA 9 in Worcester. Also picks up MA 122A, which remains after 9 splits off.
Brief multiplex with MA 101 in Ashburnham.
Multiplex with MA 2A in Fitchburg. Picks up MA 31 as well.
Cosigned with MA 62 in Sterling.
Multiplexed with MA 110 in West Boylston. Picks up MA 140 for most of the length of the multiplex.
Cosigned with US 20 in Auburn.

Originally NE-12. Basically the same routing since. In 1930, went north through Worcester via Southbridge, Main and Grove Streets. By 1950, it had been moved to Park Ave all the way through town, as it is now.

Kurumi’s CT 12 entry