U.S. Route 3

U.S. Route 3
US 3 highlighted in red
Route information
Maintained by MassDOT
Length:	277.90 mi (447.24 km)
Existed:	1926 – present
Major junctions
South end:	Route 2A / Route 3 in Cambridge, MA
	I‑95 / Route 128 / Route 3A in Burlington, MA I‑495 / Lowell Connector in Chelmsford, MA Everett Turnpike in Nashua, NH NH 101 near Manchester, NH US 202 in Concord, NH US 4 near Concord, NH I‑93 in Franconia, NH US 302 in Carroll, NH US 2 in Lancaster, NH
North end:	Route 257 near Chartierville, Quebec
Location
States:	Massachusetts, New Hampshire
Highway system
United States Numbered Highway System List Special Divided Replaced Massachusetts State Highway System Interstate US State New Hampshire Highway System Interstate U.S. State Turnpikes ← Route 2A MA Route 3 → ← US 2 NH NH 3A → ← Route 5 N.E. Route 6A →

U.S. Route 3 (US 3) is a United States highway running 277.9 miles (447.2 km) from Cambridge, Massachusetts, through New Hampshire, to the Canada–US border near Third Connecticut Lake, where it connects to Quebec Route 257.

In New Hampshire, 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. A second freeway portion exists in northern New Hampshire, where US 3 utilizes the Franconia Notch Parkway, overlapping Interstate 93.

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 MassDOT, with mileposts increasing continuously from Cape Cod all the way to the New Hampshire state border.

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 "south" (actually east) as Route 3 towards downtown Boston, while US 3 heads west, then north along the river towards downtown Cambridge, joining with Route 2 along the way. It runs opposite Soldiers Field Road in Allston along this stretch. Passing south of the downtown area, US 3 and Route 2 transition onto the Fresh Pond Parkway and join Route 16 in a wrong-way concurrency (heading north on US 3, one is also heading west on Route 2 and east on Route 16). Near the Alewife MBTA station, Route 2 splits off as a freeway to the west (Concord Turnpike), while US 3 / Route 16 turn onto the Alewife Brook Parkway. Shortly thereafter, US 3 splits from the Parkway (which continues as Route 16) and joins Route 2A (Massachusetts Avenue) westbound, crossing into Arlington. In the center of town, US 3 and Route 2A split from Massachusetts Avenue and overlap briefly with Route 60 (in another wrong-way concurrency) before continuing along Mystic Street. Route 2A splits from US 3 just to the north. US 3 continues through parts of Winchester and Woburn without any major intersections before entering Burlington and interchanging with Interstate 95 / Route 128 (Yankee Division Highway) at exit 33. US 3 joins the freeway to connect with the Northwest Expressway, while its historic surface alignment continues as Route 3A.