Webster to Revere via Milford, Newton and Medford.
Multiplex with MA 126 through Holliston.
Brief multiplex with MA 2 in Cambridge.
Very brief multiplex with MA 122 in Uxbridge.
Brief multiplex with MA 27 in Sherborn.
Cosigned with MA 38 in Medford.
Brief multiplex with MA 135 in Wellesley.
Brief multiplex with MA 1A in Revere.
In 1933, the western end was in Holliston; the eastern end was in Brookline or Boston; it came in along Beacon St. 126 took the routing to Uxbridge; Uxbridge to Webster existed but not as a numbered route. By 1939, it had been extended to Uxbridge. In Boston, it was routed up onto Mt. Auburn St, up the Alewife Brook Parkway, down Mystic Ave to the Mystic Valley Parkwayto end at Fellsway. By 1946, the west end was out to Webster. Around 1971, MA 1A was moved and 16 was extended onto the Revere Beach Parkway as it is now.