RI border in Attleboro to NH border in Salisbury via N. Attleboro, Norwood, Boston, Revere, Danvers and Newburyport.
Paired along I-95 as a reverse multiplex in Norwood and Canton.
Paired with I-93 from its southern terminus north to the Tobin Bridge. Follows original planned route for I-95 north of Boston to Revere.
Cosigned with MA 1A from Attleboro to North Attleboro, and again in Salisbury.
Cosigned with MA 129 in Saugus and Lynnfield.
Divided highway with at-grade intersections north of Revere to Danvers.
Originally NE-1 (New England Insterstate Highway 1), signed in 1923. In 1927, NE-1 was redesignated as US Highway 1. South of Boston, the route is largely unchanged since it was created. In 1933, US 1 entered Boston on Ames St, up Bridge, Spring and Centre (Bridge, Spring and Center were bypassed by the VFW Parkway by 1936, and Rt 1 was put on there). to the Jamiacaway. It passed along Comm Ave inbound, passed over the Charles on the Mass Ave Bridge and took a right onto Memorial Drive. From there, it took the Northern Traffic Artery to Cambridge street. North of Boston, it exited via Broadway and the Newburyport Turnpike.
Between 1953 and 1956, a new highway had been completed north of Boston, from Danvers to the NH border. US 1 was put onto the highway; the old US 1 became MA 17. In 1958, I-95 was also added to this highway. By 1959, US 1 was back on its old routing north of Danvers.
In 1971, C1 was eliminated. US 1 was routed along its route, through downtown Boston, through the Sumner & Callahan tunnels and up the McClellan highway to the Bennett and back to Broadway in Saugus. MA 99 was designated on the stretch of Broadway formerly known as US 1. MA 16 picked up the Revere Beach Parkway (including 1A‘s section). MA 28 took the B and O’Brien highways back to Boston.
By 1975, the construction of I-95 from Boston to Peabody had been cancelled. A short section from the Tobin Bridge to Revere, had been built. US 1 was put onto this. 1A picked up the section of US 1 south of their intersection back into Boston. The small piece of former US 1 between these two points was given to MA 60.