New Hampshire ), looking south I-89 runs for about in the state of New Hampshire and is the major freeway corridor through the western part of the state. Despite being signed as a north–south freeway, its first actually run east–west before shifting to the northwest. The two major population centers along I-89's length in New Hampshire are
Concord, at its southern terminus, and
Lebanon, on the Vermont state line. Mileage signs along I-89 in each direction consistently list one of the two cities. Also located along I-89 in New Hampshire are the towns of
Grantham,
New London, and
Warner. Starting at an interchange with
I-93 and
New Hampshire Route 3A (NH 3A) in the town of
Bow, just south of the
New Hampshire capital city of Concord, the highway runs a northwest path through the
Dartmouth–Lake Sunapee Region. One exit directly serves Concord (exit 2) before the highway enters the neighboring town of
Hopkinton. East–west
NH 11 joins I-89 at exit 11 and runs concurrently with it for about before departing at exit 12. At exit 13 in Grantham,
NH 10 enters I-89, and the pair of highways form another concurrency, this one for about . Southeast of Lebanon, signs for exit 15 display the name "Montcalm", while exit 16 directs travelers to "Purmort". Neither place name existed at the time of construction of the Interstate. Exits 15 and 16 were built to access portions of the town of
Enfield that were otherwise cut off by the new highway. The names were chosen by Enfield's
selectpeople in 1960; the Purmorts were a prominent local family in the early history of Enfield, and Montcalm was a nearby settlement that had once had its own school and post office. While the Purmort exit does allow access to the state road network (specifically to
US 4 via Eastman Hill Road), the Montcalm exit provides access to an otherwise isolated community; every public road from the exit is a dead-end, and leaving the Montcalm area by car requires getting back on I-89 at exit 15. However, a
bicycle path parallels I-89 between exits 14 and 16 along the path of Old Route 10, allowing foot or bicycle access to the community. The highway continues northwest, passing through Lebanon, in which the
Dartmouth–Hitchcock Medical Center is located. A few miles north of this point is
Dartmouth College. US 4 parallels I-89 through Lebanon. Exits 17 through 20 serve the city of Lebanon and are passed in quick succession. At exit 19, northbound
NH 10 separates from I-89 and joins westbound US 4 to pass through
West Lebanon. The final exit in New Hampshire is exit 20, providing access to West Lebanon's large retail district along
NH 12A. Just after this interchange, the highway crosses the
Connecticut River and enters
Vermont, where it remains for the rest of its run northwest to the Canadian border.
Vermont (June 5, 2015), Chittenden County I-89 is one of Vermont's most important roads, as it is the only Interstate Highway to directly serve both Vermont's capital city (
Montpelier) and largest city (
Burlington). Other important cities and towns located along I-89 are
Barre,
Waterbury, and
St. Albans.
Williston, which has become Burlington's
big-box retail center (and one of the fastest-growing towns in the state) over the past decade, also has an interchange along I-89. Crossing the
Connecticut River into Vermont, I-89 continues the northwesterly direction it carried in New Hampshire. The Interstate intersects
I-91 at a previously unnumbered interchange (now exit 1) immediately upon entering Vermont. Shortly afterward, another interchange with
US 4 occurs. The highway begins to enter the scenic rolling hills of Vermont, turning almost due northward about from the New Hampshire state line, and continues through the high country of central Vermont. The Interstate passes through the towns of
Sharon,
Royalton,
Bethel,
Randolph,
Brookfield, and
Williamstown before reaching the "twin cities" of Barre and Montpelier in the middle of Vermont. The Interstate's highest point was said to be in the town of Brookfield, although the sign that made the declaration was taken down in the late 1990s. Another directional shift, again to the northwest, occurs while passing the interchange for Montpelier. For the next , I-89's path is not so much chosen as it is logical: paralleling the
Winooski River and
US 2, the highway cuts through the section of the
Appalachian Mountains known as the
Green Mountains, and is surrounded by peaks of over :
Camel's Hump to the south and
Mount Mansfield to the north. US 2 crosses the Interstate frequently, and has several interchanges with it, en route to Burlington. I-89 was unique due to one instance of its signage. Between (Vermont) exits 9 and 10, a sign showing the distance to the next control cities in each direction was completely in metric. While there are many instances of signs being in both miles and kilometers, this was the only case of solely metric in the entire Interstate System. Both signs were replaced in 2010 and show distances in miles only. (
I-19 in
Arizona used to be the other "only signed in metric" Interstate in the US, but has been changed over in recent years as the last two kilometers have been changed.) Speed limit signs have always been posted in miles per hour. along I-89 northbound in
South Burlington, just west of exit 12 After exit 11 in
Richmond, I-89 leaves the Green Mountains to enter the
Champlain Valley, and a notable shift in the landscape is visible. Here, just outside
Burlington, the highway turns northward once again. Also, at this turn is where the only
official auxiliary highway starts,
I-189. A second highway,
I-289, was proposed as a beltway through Burlington's northeastern suburbs in the 1980s; amid controversy, the highway has only been partially completed as
Vermont Route 289 (VT 289), a
super two roadway. It has yet to directly meet its parent. Passing I-189 at exit 13, I-89 sees the busiest freeway interchange in the entire state, exit 14. A full
cloverleaf interchange at this exit provides access to downtown Burlington, the
University of Vermont, and the retail-heavy Dorset Street, via US 2. Heading north from Burlington, the landscape quickly fades from suburban development into rolling hills more characteristic of northern New England, providing a vista overlooking
Lake Champlain. I-89 passes through
Milton,
Georgia,
St. Albans,
Swanton, and finally the border town of Highgate Springs. The highway ends at the Canada–United States border at the
Highgate Springs–St. Armand/Philipsburg Border Crossing in
Highgate Springs. Its final exit, which northbound motorists can use to reverse direction onto I-89 south without crossing the border, is exit 22—the highest exit number along the route.
US 7 has its northern terminus at this interchange as well. The divided highway continues about into
Philipsburg, Quebec, as a
dual carriageway-section of
Route 133, then changes to
Autoroute 35 and continues to
Saint-Jean-sur-Richelieu and
Chambly before it meets
Autoroute 10, which goes to
Montreal. The I-89 border crossing is the only instance where an Interstate entering Quebec does not become an
Autoroute upon entry. There were plans to complete the extension of Autoroute 35 from Saint-Sébastien to the border crossing at I-89's northern terminus in 2025, creating a freeway-to-freeway connection, but the final phase was indefinitely postponed in March 2025. ==History==