Massachusetts Route 3A

Route 3A
Route 3A highlighted in red
Route information
Maintained by MassDOT
Length	97 mi[1] (156 km)
Existed	1926–present
Southern section
Length	53.392 mi[1] (85.926 km)
South end	Route 3 in Plymouth
Major intersections	US 44 in Plymouth Route 53 in Kingston Route 53 in Quincy
North end	I-93 / US 1 / Route 3 / Route 203 in Boston
Northern section
Length	22.5043 mi[1] (36.2172 km)
South end	I-95 / US 3 / Route 128 in Burlington
Major intersections	Lowell Connector in Lowell Route 110 in Lowell Route 113 in Tyngsborough
North end	NH 3A in Hudson, NH
Location
Country	United States
State	Massachusetts
Counties	Plymouth, Norfolk, Suffolk, Middlesex
Highway system
Massachusetts State Highway System Interstate US State
← Route 3 → Route 3B
← Route 6 N.E. → Route 7

Route 3A is a 97-mile-long (156 km) state highway in eastern Massachusetts, which parallels Route 3 and U.S. Route 3 from Cedarville in southern Plymouth to Tyngsborough at the New Hampshire state line.

Route 3A has two major posted segments, separated by a lengthy concurrency with Route 3 and US 3. Its southern portion parallels Route 3 from Cedarville in southern Plymouth to Neponset in the Dorchester area of Boston. Towns and cities that Route 3A traverse along its path include Plymouth, Kingston, Duxbury, Marshfield, Scituate, Cohasset, Hingham, Weymouth and Quincy.

North of Neponset, Route 3A runs, unsigned, concurrently with Route 3 and U.S. Route 3 to Burlington, before separating again (MassDOT counts the mileage along MA 3 and US 3 between the two sections as part of MA 3A mileage).

The northern portion of Route 3A parallels U.S. Route 3 in northwestern Middlesex County. It stretches from Interstate 95 (Route 128) in Burlington to the New Hampshire state line, where it continues as Route 3A.