I-93

I-93 is a major north–south Interstate Highway in the New England region of the United States. It runs for approximately 190 miles from Canton, Massachusetts, to St. Johnsbury, Vermont, serving as a critical transportation artery through the heart of Boston and into the White Mountains. The highway connects key cities including Boston, Manchester, and Concord, while also providing access to recreational areas in New Hampshire and Vermont.

Route description

Beginning at a complex interchange with I-95 and US 1 in Canton, the route heads northward through the densely populated suburbs south of Boston. It enters the city proper, where it is concurrently signed with US 1 and MA 3, passing through the Thomas P. O'Neill Jr. Tunnel and the Leonard P. Zakim Bunker Hill Memorial Bridge, iconic features of the Big Dig project. North of Boston, it passes through cities like Medford and Andover before crossing into New Hampshire near Salem. Through New Hampshire, it serves the Merrimack Valley cities of Manchester and Concord, then continues north through the scenic Franconia Notch in the White Mountain National Forest. It finally crosses into Vermont and terminates at an intersection with US 2 in St. Johnsbury.

History

The highway's origins lie in the post-war Federal-Aid Highway Act of 1956, which authorized the construction of the Interstate Highway System. Initial segments in Massachusetts and New Hampshire were completed and opened to traffic in the late 1950s and early 1960s. One of the most significant and costly chapters in its history is its reconstruction through downtown Boston as part of the Central Artery/Tunnel Project, commonly known as the Big Dig. This massive undertaking, which lasted from 1991 to 2007, replaced an elevated highway with an underground tunnel system to alleviate congestion and reconnect the city. In New Hampshire, the routing through the environmentally sensitive Franconia Notch was the subject of protracted debate, resulting in a unique parkway-style design to preserve the natural beauty of the area, managed by the New Hampshire Department of Transportation.

Major intersections

From south to north, key junctions include the southern terminus at I-95/US 1 in Canton. In Boston, major interchanges exist with I-90 (the Massachusetts Turnpike) and US 1. North of the city, it intersects with I-495 in Andover. After crossing into New Hampshire, it meets the termini of I-293 and I-393 near Manchester and Concord, respectively. Further north, it has a junction with US 3 in Franconia Notch. In Vermont, its final major intersection is with I-91 in St. Johnsbury just before ending at US 2.

Auxiliary routes

Several three-digit auxiliary Interstate Highways branch from this route to serve metropolitan areas. In Massachusetts, I-293 forms a loop through Manchester and Bedford, New Hampshire, while I-393 provides a spur from Concord east toward Gilmanton. Although not directly connected, I-293 also links to the Everett Turnpike, a critical toll road in southern New Hampshire. These auxiliary routes help distribute traffic from the mainline to key commercial and residential centers, forming an integral part of the regional highway network managed by state departments of transportation like the Massachusetts Department of Transportation and the New Hampshire Department of Transportation.

Category:Interstate Highways Category:Transportation in Massachusetts Category:Transportation in New Hampshire Category:Transportation in Vermont