Interstate 91
Interstate 91 is an Interstate Highway in the New England region of the United States. It is the primary north–south thoroughfare in the western part of the region. Its southern terminus is in New Haven, Connecticut, at I-95, while its northern terminus is in Derby Line, Vermont, at the Canada–United States border. Past the Derby Line–Rock Island Border Crossing, the road continues into Canada as Quebec Autoroute 55. I-91 is the longest of three Interstate highways whose entire route is located within the New England states and is also the only primary Interstate Highway in New England to intersect all five of the other interstate highways that run through the region. The largest cities along its route, from south to north, are New Haven, Connecticut; Hartford, Connecticut; Springfield, Massachusetts; Northampton, Massachusetts; Greenfield, Massachusetts; Brattleboro, Vermont; White River Junction, Vermont; St. Johnsbury, Vermont; and Newport, Vermont.
Route description
Connecticut
I-91 is the major north–south transportation corridor for the center of the state. It is the main route between the larger cities of New Haven, Hartford, and Springfield, Massachusetts. As such, it is almost always heavily trafficked and maintains at least three lanes in each direction through Connecticut except for a short portion in Hartford at the interchange with I-84, and another in Meriden at the interchange with Route 15. The three cities also serve as Connecticut's control points along its length of the Interstate.I-91 begins just east of Downtown New Haven at an interchange with I-95. At the bottom of the ramp for exit 5, US 5 begins at the first of its many interchanges with the freeway. Leaving New Haven, I-91 follows a northeastward trek into North Haven, where it meets the southern end of the Route 40 expressway. It travels through the eastern part of Wallingford before entering the eastern part of the city of Meriden. In Meriden, about halfway between Hartford and New Haven, I-91 sees a complex set of interchanges with the Wilbur Cross Parkway, the Route 66 expressway, and its first spur route, I-691. I-691 provides a westward link to I-84 and the city of Waterbury. Leaving Meriden, I-91 enters Middlesex County as it briefly travels through the western part of Middletown before entering Cromwell, where it has an interchange with the Route 9 expressway.
It then enters Hartford County in the town of Rocky Hill and then enters Wethersfield, meeting the Route 3 expressway, which leads to Glastonbury and the Route 2 expressway via the William H. Putnam Memorial Bridge over the Connecticut River. From there to St. Johnsbury, Vermont, I-91 parallels the river, never more than from its west bank. I-91 then enters the Hartford city limits; in that city, it has a set of interchanges with US 5/Route 15, which provides access from I-91 north to I-84 east, and from I-84 west to I-91 south via the Charter Oak Bridge. I-91 then has an interchange with I-84, where all other transitions to and from I-84 take place. Before leaving the city limits, a high-occupancy vehicle lane begins that has its own set of interchanges up to exit 38.
I-91 then enters Windsor and meets the western end of its other Connecticut spur route, I-291. At the Windsor–Windsor Locks town line, it meets the eastern terminus of the Route 20 expressway, which provides direct access to Bradley International Airport. A couple of miles further north, I-91 crosses the Connecticut River on the Dexter Coffin Bridge into East Windsor. After traveling through East Windsor and Enfield, it crosses the state line, at milepost 58, into Longmeadow, Massachusetts.
Massachusetts
I-91 extends through the Pioneer Valley of western Massachusetts paralleling the Connecticut River. I-91 serves as the major transportation corridor through three Massachusetts counties, linking the cities of Springfield, Northampton, and Greenfield. These three cities serve as the control cities listed on guide and mileage signs, along with Brattleboro, Vermont, beginning with the first northbound conventional mileage sign in Longmeadow.In Springfield, I-91 has an interchange with I-291 at exit 6, a spur going eastbound to connect with the Massachusetts Turnpike, for travelers going either east toward Boston or west toward Albany, New York. North of Springfield, I-91 briefly enters Chicopee, there is an interchange with its spur, I-391, at exit 9 before turning westward to cross the Connecticut River into West Springfield. I-391 provides direct access to Holyoke, while I-91 continues on the western side of the river.
Just after the river crossing, exit 11 is a major interchange with the Massachusetts Turnpike. Then, I-91 enters the city of Holyoke where exit 12 is located. Just after an interchange with US 202, I-91 goes from three lanes to two lanes in each direction to the Vermont state line. After a short exit-less stretch, I-91 enters Northampton, passing the Northampton Airport and an oxbow lake. The towns of Hadley and Amherst, home to the main campus of the University of Massachusetts Amherst, are accessible from I-91 exits in Northampton via Route 9.
Continuing north, I-91 enters Hatfield, where it begins a straight section—nearly without a bend in the road. Several exits provide access to US 5 and Route 10 in Hatfield and Whately before entering Deerfield. I-91 has two exits in Greenfield. At exit 43, the southern end of its overlap with Route 2, there is a rest area and visitor information center for Franklin County. At exit 46, also in Greenfield, is the northern end of its overlap with Route 2 where access to that road is provided via a directional T interchange and exit and entry ramps on the left side of southbound I-91. Exit 50 in Bernardston is the last exit in Massachusetts. Beyond exit 50, I-91 continues for about more before crossing into Vermont.
Massachusetts is the only state traversed by I-91 where another numbered highway is concurrent with the Interstate.
Vermont
I-91 traverses the entire length of Vermont and serves as a major transportation corridor for eastern Vermont and western New Hampshire. Due to its routing along the Connecticut River separating the two states, many exits along Vermont's length of I-91 feature New Hampshire towns on the guide signs. The length of I-91 within Vermont is and has two lanes in each direction the entire way from the Massachusetts state line to the Canada–United States border with 29 Vermont interchanges. The highway's rural character and long distances between exits in Vermont are in stark contrast to its south, where exits are more frequent and the road carries four lanes of traffic in each direction at some points. The major control cities in Vermont are Brattleboro, White River Junction, St. Johnsbury, and Newport. When entering northbound I-91 at exit 28 in Derby, the control city sign is for Canada. Of these destinations, only Newport is a city, although the other towns are sizable. In general, the road parallels its predecessor, US 5.I-91 enters Vermont in the town of Guilford. Just before exit 1 in Brattleboro is the Vermont Welcome Center in Guilford. The first three Vermont exits serve the town of Brattleboro. At exit 1, northbound US 5 provides access to stores and a small industrial area before reaching the south end of the town's center, where a bridge crosses the Connecticut River into Hinsdale, New Hampshire, via New Hampshire Route 119. Exit 2 provides access to the western village of the town, then continues west to Marlboro, Wilmington, and Bennington. Brattleboro's main retail strip is located at and just south of the exit 3 trumpet interchange and traffic circle. Following VT 9 eastward, one can reach Keene, New Hampshire, in.
After exit 3, I-91 heads north to travel through the communities of Dummerston, Putney, Westminster, North Westminster, Bellows Falls, Springfield, Weathersfield, Windsor, Hartland, North Hartland and White River Junction. White River Junction, listed as a control city on mileage signs as far south as Greenfield, Massachusetts, is where I-91 and I-89 meet and provide access to many points in Vermont and New Hampshire, at exit 10.
North of the interchange with I-89, I-91 continues toward St. Johnsbury and travels through Wilder and Norwich. It enters Orange County, passing through Thetford, Fairlee, Bradford, Newbury, and Wells River. It continues into the Caledonia County communities of Ryegate, Barnet and Waterford, before coming to its next major intersection in St. Johnsbury at the northern terminus of I-93, providing access to the White Mountains of New Hampshire and the Greater Boston area. Along this stretch of highway between White River Junction and St. Johnsbury, towns in Grafton County, New Hampshire, on the other side of the river can also be easily accessed. Just after exit 19, there are three exits for St. Johnsbury, including a major intersection with US 2. Along westbound US 2, the capital of Vermont, Montpelier, is eventually reached from I-91, although I-89 provides Montpelier with immediate Interstate access.
I-91 continues northward, now following the Passumpsic River valley. It travels through Vermont's Northeast Kingdom region and the town of Lyndon. Two exits in Lyndon serve the village of Lyndonville and Lyndon State College. After exit 24, I-91 departs US 5, which it had been closely paralleling since the Massachusetts state line. I-91 follows the valley of Miller Run, and there are no convenient services until Barton at exit 25.
The Interstate proceeds through Sheffield. Here, it reaches the highest point on the highway, just north of milemarker 150 on Sheffield Heights, elevation.
After leaving Sheffield Heights, it enters Orleans County and follows the Barton River valley north with exits in Barton, Orleans, and Derby. Exit 29 is the final US exit on I-91 just after milemarker 177 at Derby Line. Beyond this exit, northbound motorists enter Canada Customs at Stanstead, Quebec, and continue into Canada on Quebec Autoroute 55 through the Eastern Townships.
As with Connecticut and Massachusetts, US 5 closely parallels I-91 for their entire lengths in Vermont. While paralleling I-91 in Vermont, US 5 is never concurrent with the freeway but remains its own two-lane highway, except for a portion in White River Junction where it is a four-lane, divided, surface arterial freeway.
Traffic and the population of each successive town tend to diminish as the road proceeds northward. The average daily traffic count for 2015 in Vermont were—St. Johnsbury, Lyndon, Barton, and Derby .