U.S. Route 3 (US 3) is a United States Numbered Highway running from Cambridge, Massachusetts, through New Hampshire, to the Canada–US border near Third Connecticut Lake, where it connects to Quebec Route 257. 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 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. Route description |- | | |- | | |- |Total | |} Massachusetts Cambridge to Burlington US 3 begins in the south along Memorial Drive in Cambridge, along the Charles River, at an interchange with Massachusetts Avenue (Route 2A). The road continues as southbound Route 3 toward Downtown Boston, while northbound US 3 heads west, then north along the river toward Harvard University, joining with Route 2 along the way. It runs along the north bank of the Charles River, opposite Soldiers Field Road in Allston along this stretch. Passing south of Harvard Square, US 3 and Route 2 transition onto the Fresh Pond Parkway and join Route 16. Near Alewife station,