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, Route 2 splits off as a
freeway to the west (Concord Turnpike), while US 3 and Route 16 stay on 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 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
I-95 and
Route 128 (Yankee Division Highway) at exit 51A. US 3 joins the freeway to connect with the Northwest Expressway, while its historic surface alignment continues as
Route 3A.
Burlington to Tyngsborough (Northwest Expressway) and
Massachusetts Route 110 in
Chelmsford US 3 runs along of I-95 (Route 128) in a
wrong-way concurrency before exiting at exit 50A onto its own freeway, the Northwest Expressway. Originally built in the 1950s, before the cancelation of the
Inner Belt, the US 3 freeway was to have extended into metro Boston before being truncated to I-95. Consequently, a partially completed
cloverleaf interchange connects US 3 to I-95. Exit numbers on the US 3 freeway start at milemarker 72 since Route 3 and US 3 are counted as one highway by MassDOT. The freeway closely parallels Route 3A, the historic alignment of US 3, along its entire length from Burlington to the
New Hampshire state border. It passes through
Billerica and into
Chelmsford, where it connects with
I-495 and the
Lowell Connector, a freeway spur into downtown
Lowell. Continuing north, the freeway briefly enters Lowell, then passes through
North Chelmsford and
Tyngsborough before crossing the
state line into
Nashua, New Hampshire. The freeway continues north as the
Everett Turnpike. The Burlington to Tyngsborough area maintains a
501(c)(6) nonprofit representative entity known as the Middlesex 3 Coalition and its affiliate agency the Middlesex 3 TMA, which provides collaborative support to businesses and individuals within the jurisdiction to build consensus on transportation and developmental needs.
New Hampshire US 3 passes through most of the state's major cities and towns and is the only highway to extend from the
Massachusetts state border in the south to the Canadian border in the north. Running for in New Hampshire, US 3 is by far the longest signed highway in the state. For much of its routing, US 3 closely parallels I-93, serving as a local route to the freeway.
Everett Turnpike (Nashua) US 3 crosses the state border into
Nashua and immediately becomes concurrent with the
Everett Turnpike, running on the freeway for along the western side of the city.
Daniel Webster Highway, local roads, and NH 28 concurrency (Nashua – Suncook) US 3 leaves the Everett Turnpike at exit 7E, crosses
New Hampshire Route 101A (NH 101A) and turns northeast for approximately along a segment known as the Henri Burque Highway, before turning north onto Concord Street, which soon becomes known as the
Daniel Webster Highway. (Some locals erroneously refer to the Everett Turnpike from exit 7 through the
I-293 interchange as US 3 and refer to the actual US 3 only as the Daniel Webster Highway or "Old Route 3".) US 3 continues north through the town of
Merrimack and into
Bedford, where it becomes South River Road. The highway parallels I-293 until it turns east in
Manchester and then crosses the
Merrimack River on Queen City Avenue, just after its intersection with I-293/
NH 3A and
NH 114A. US 3 and NH 3A are signed in a wrong-way concurrency for approximately before US 3 turns north onto Elm Street toward downtown Manchester. After approximately , US 3 turns east onto Webster Street, then joins
NH 28 to proceed in a northeasterly direction toward Hooksett, interchanging with
I-93. The two routes continue as Hooksett Road, then the Daniel Webster Highway.
In Concord In
Suncook, NH 28 leaves to the northeast, and US 3 proceeds northwest toward
Concord on Pembroke Street, becoming Manchester Street when it enters the Concord city limits. After crossing the Merrimack River and interchanging with I-93, US 3 intersects NH 3A (South Main Street), which terminates at its parent route. US 3 traverses downtown Concord as North and South Main streets (briefly overlapping with
US 202 and
NH 9), then follows North State Street to Fisherville Road to Village Street in
Penacook before crossing the
Contoocook River into
Boscawen.
Further north (Boscawen – Lincoln) US 3 travels north through Boscawen, briefly overlapping with
US 4. The highway parallels the Merrimack River north into
Franklin, where the highway meets
NH 11. US 3 joins NH 11 and turns east; NH 3A also resumes at this intersection, continuing north. US 3 and NH 11 briefly form a three-route concurrency with
NH 127 in Franklin, then pass through
Tilton, crossing
NH 132 and passing the western end of
NH 140. Continuing northeast past
Lake Winnisquam, US 3 and NH 11 reach
Laconia and turn onto the Laconia–
Gilford Bypass, intersecting with
NH 106,
NH 107, and
NH 11A. At the northern end of the bypass, US 3 and NH 11 split after a overlap, with the U.S. Route continuing north on Lake Street to
Weirs Beach and an intersection with
NH 11B. US 3 continues north as the
Daniel Webster Highway to
Meredith at the northern end of Meredith Bay on
Lake Winnipesaukee. In Meredith, US 3 intersects the northern terminus of NH 106, then joins
NH 25 and continues north past
Squam Lake into
Holderness, passing the western terminuses of
NH 25B and
NH 113. Through Holderness, US 3 and NH 25 gradually turn west, then southwest, passing the southern end of
NH 175 and then reaching the northern end of
NH 132 in
Ashland. From Ashland to
North Woodstock, US 3 proceeds north, roughly paralleling
I-93 in the
Pemigewasset River valley. Along this stretch it passes through the towns of
Plymouth (NH 25 splits from US 3 near I-93 in Plymouth, which also marks the true northern terminus of NH 3A),
West Campton (where it meets the western end of
NH 49, the principal access road to
Waterville Valley),
Thornton, and
Woodstock. In
North Woodstock, US 3 crosses
NH 112 (known to the east as the
Kancamagus Highway).
Interstate 93 concurrency through the Franconia Notch State Park (Lincoln – Franconia) Continuing north, US 3 joins with I-93 as it passes through
Franconia Notch State Park, one of the more scenic drives in the
White Mountains. This stretch of freeway is known as the Franconia Notch Parkway and is a rare section of
Interstate Highway with only one lane in each direction.
Northernmost end (Franconia – Pittsburg) US 3 separates from I-93 at exit 35, shortly north of the northern park boundary in
Franconia. From there,
NH 141 branches northwest and US 3 heads north and east toward
Twin Mountain and a junction with
US 302. This portion of the road is noted for fairly frequent
moose sightings, especially during sunrise and sunset when moose are particularly active. Heading north from Twin Mountain, US 3 passes through the village of
Carroll, where
NH 115 branches to the northeast and US 3 bears to the northwest and the town of
Whitefield. In the center of Whitefield,
NH 142 branches to the northwest and
NH 116 crosses, running roughly southwest to northeast. US 3 continues north to
Lancaster, where it joins
US 2 in the town center, and where
NH 135 branches off to the west. After US 2 leaves to the west, US 3 continues north, roughly paralleling the course of the
Connecticut River (which also forms the border with
Vermont), through
Northumberland and
Groveton, where
NH 110 ends. North of Groveton, US 3 continues to follow the river, through
Stratford,
North Stratford, and
Columbia, until it reaches
Colebrook, where it crosses
NH 26 and meets the southern terminus of
NH 145. Still following the Connecticut River north, US 3 passes through portions of
Stewartstown and
Clarksville. In Stewartstown, the road turns more directly east (still following the Connecticut River, which is no longer a boundary), before resuming a northeasterly direction through
Pittsburg. Its last major intersection is at the northern terminus of NH 145. US 3 continues north for another , eventually reaching the
Pittsburg–Chartierville Border Crossing, where the road crosses into
Chartierville, Quebec, and becomes
Quebec Route 257. In total, US 3 runs along the Connecticut River and its source lakes for approximately . Sections of US 3 in Colebrook are named after Scott E. Phillips and Leslie G. Lord, members of the
New Hampshire State Police killed in the line of duty on
August 19, 1997. ==History==