U.S. Route 3

U.S. Route 3
U.S. Route 3
	US 3 highlighted in red and US 3 Bus. highlighted in blue
Route information
Length	277.90 mi[citation needed] (447.24 km)
Existed	1926[citation needed]–present
Major junctions
South end	Route 2A / Route 3 in Cambridge, MA
	Route 2 / Route 16 in Cambridge, MA; I-95 / Route 128 / Route 3A in Burlington, MA; I-495 / Lowell Connector in Chelmsford, MA; Everett Turnpike in Nashua, NH; I-293 / Everett Turnpike / NH 101 near Manchester, NH; US 202 / US 4 in Concord, NH; I-93 in Franconia, NH; US 302 in Carroll, NH; US 2 in Lancaster, NH;
North end	R-257 near Chartierville, Quebec
Location
Country	United States
States	Massachusetts, New Hampshire
Counties	MA: Middlesex; NH: Hillsborough, Merrimack, Belknap, Grafton, Coös
Highway system
	United States Numbered Highway System; List; Special; Divided;
	New Hampshire Highway System; Interstate; US; State; Turnpikes;

U.S. Route 3 (US 3) is a United States Numbered Highway running 277.90 miles (447.24 km) from Cambridge, Massachusetts, through New Hampshire, to the Canada–United States border near Third Connecticut Lake, where it connects to Quebec Route 257.

Massachusetts Route 3 connects to the southern terminus of US 3 in Cambridge and continues south to Cape Cod. Though it shares a number, it has never been part of US 3. Both routes, which connect end-to-end, are treated as a single 91.3-mile (146.9 km) state highway by the Massachusetts Department of Transportation (MassDOT). From Cambridge to Burlington, US 3 is routed on surface streets through the dense suburbs in the Greater Boston area. After a brief concurrency with Interstate 95 (I-95) and Route 128, the route follows its own freeway northwest, bypassing Lowell and entering New Hampshire at Nashua, becoming the Everett Turnpike.

In New Hampshire, current and former parts of US 3 are known as the Daniel Webster Highway. From Burlington, Massachusetts, to Nashua, New Hampshire, US 3 is a freeway. The segment in New Hampshire is a free portion of the Everett Turnpike, while the portion in Massachusetts is known as the Northwest Expressway. From where it leaves the Everett Turnpike in Nashua northward, US 3 is generally a two-to-four lane at-grade road, though there are two super-two freeway portions in northern New Hampshire, one on the Laconia Bypass, and one where US 3 and I-93 use the Franconia Notch Parkway. The route serves as a major local arterial, connecting many of the cities of the densely populated Merrimack Valley. North of the White Mountains, the route serves as one of the only north–south roads connecting the communities of the Great North Woods Region and has New Hampshire's only border crossing between the US and Canada.