A New England intra-regional highway, Interstate 93 serves the Boston metropolitan area, northern Massachusetts through Lawrence, the state of New Hampshire, and the Northeast Kingdom of Vermont. The freeway provides a direct connection to Canada in conjunction with Interstate 91 north of St. Johnsbury, Vermont.
Built as part of the Big Dig project, the Thomas P. O’Neill, Jr. Tunnel carries 1.5 miles of Interstate 93 below central Boston. The tunnel runs between Kneeland and Causeway Streets, directly linking with the Leonard P. Zakim Bunker Hill Bridge opened in 2003.
Through the White Mountains and Franconia Notch in northern New Hampshire, Interstate 93 transitions into a parkway, with a reduced right-of-way and two and three lane sections. Nine miles long, Franconia Notch Parkway runs between Exit 33 (U.S. 3 north of Lincoln) and Exit 35 (NH 18 near Echo Lake). This exception to Interstate standards allows the freeway to intrude minimally on the sensitive areas of the Notch, including the former Old Man of the Mountain, which collapsed on May 3, 2003. Recreational areas are accessible along this stretch at Exits 34A, 34B and 34C.
The Big Dig
Interstate 93 through Downtown Boston was reconstructed in one of the most expensive and dramatic projects in highway history. Known as “The Big Dig,” this megaproject resulted in the removal of the Fitzgerald Expressway, the elevated “green elephant” through Downtown (though part of the double deck in Charlestown remains). Traffic was relocated to a system of tunnels, as well as a new ten lane (six lanes northbound, four lanes southbound) cable-stayed Leonard P. Zakim Bridge over the Charles River, plus the four-lane Leverett Circle Connector bridge. This new span replaced the original six-lane double decker bridge.
No ceremonies were held as the last section of new freeway for Interstate 93 opened to traffic. The December 20, 2003 completion of the southbound lanes through the tunnel system marked the end of the $14.6 billion project. The often controversial project was $4 billion over budget, and the source of bitterness among residents and politicians alike. With origins in 1987, the Big Dig even raised concerns of then President Ronald Reagan because of its overwhelming cost. Nonetheless, after years of construction, the two mile system of underground roadways built during the Big Dig resulted in the removal of a city eyesore and traffic nightmare.1
With the removal of the Fitzgerald Expressway, one and half miles of green space was created within its former footprint. This resulted in eight acres of public park space and additional land made available for new housing, shops and cultural venues. Collectively 7.5 miles long, all in all 16 million cubic yards of dirt were excavated for the new tunnel system.1
Unfortunately, the Big Dig had a lasting legacy. Its underwater tunnels had a tendency to leak and the project managers (Bechtel and Parsons Brinckerhoff) were accused of making decisions that resulted in extraordinary costs for the project. Cost overruns led NBC News to refer to this project repeatedly on its “Fleecing of America” segment. The Boston Globe provides more detailed information on the Big Dig in the “Big Dig Report.”
The White Mountains
The northern portion of Interstate 93 in New Hampshire, from Plymouth to the Vermont state line, travels through the picturesque White Mountains. The section that runs along Franconia Notch Parkway is technically not a part of I-93, as it does not meet full Interstate standards. The parkway design was the result of a compromise between the park service and highway department. Maintained as a limited access highway, side access along the parkway is restricted to interchanges and designated parking areas.
When originally constructed, Franconia Notch Parkway used a separate exit numbering system from the rest of Interstate 93. According to Jeffrey Moss this changed in 2002 when Exits 1, 2 and 3 were renumbered to confirm with the rest of I-93. Aside from brown guide signs and the narrowing of the freeway, the transition to Franconia Notch Parkway along Interstate 93 is nearly invisible to the motoring public, so a separate exit number system made little sense.
Parallel U.S. Routes
Interstate 93 primarily bypasses communities along U.S. 3 in Massachusetts and New Hampshire. Where the freeway turns westward toward Vermont at Littleton, it briefly parallels U.S. 302. U.S. 2 accompanies the northernmost reaches of the freeway corridor through the town of St. Johnsbury.
The first portion of Interstate 93 constructed in Massachusetts extended 24 miles north from Medford to the New Hampshire state line. Costing $47 million, work ran from 1956 to 1963. Delays ensued on the three mile link southward to the Northeast Expressway (then Interstate 95) due to the relocation of residents and businesses along the corridor. It eventually opened in 1973, around the same time that plans for I-95 within the Route 128 beltway (Yankee Division Highway) were dropped.5 This resulted in an extension of Interstate 93 southward along both the John F. Fitzgerald and Southeast Expressways to Braintree and west along the Yankee Division Highway to I-95 at Canton. AASHTO endorsed the extension south from the Boston/Somerville city limits to Route 128 in Braintree on June 17, 1975, and the extension west along Route 128 on November 15, 1975.
Interstate 93 along the Everett Turnpike, from Manchester north to Concord in New Hampshire, opened to traffic in August 1957.2 Subsequent portions of I-93 through the Granite State opened between Salem and Manchester, and Bow and Tilton, by 1963.3 The route was completed in New Hampshire on June 2, 1988, when Franconia Notch Parkway was dedicated.3
Within Vermont, the 11-mile stretch of Interstate 93 leading west to St. Johnsberry opened on October 29, 1982 after delays caused by agricultural lawsuits.4 I-93 would have been longer had I-91 been built further west toward Danville as originally envisioned. The planned corridor for Interstate 91 shifted eastward in 1963.
North End – St. Johnsbury, VT
South End – Boston, MA
Branch Routes – 2
Total Mileage – 189.95
Massachusetts – 47.07
- Cities – Boston, Lawrence
New Hampshire – 131.78
- Cities – Manchester, Concord, Franklin, Plymouth, Littleton
Vermont – 11.10
Cities – St. Johnsbury
- Junctions –
Source: December 31, 2018 Interstate Route Log and Finders List
I-93 Annual Average Daily Traffic (AADT)
Source: Traffic Volume Reports 2014-15 AADT NHDOT
Interstate 93 was open from Medford north to the New Hampshire state line in 1963. The route southward was completed to the Northeast Expressway on February 1, 1973.5
Two portions of Interstate 93 were open north of New Hampton, New Hampshire in 1964: a short bypass of U.S. 3 between Plymouth and Campton and the northwestern alignment from U.S. 3 near Franconia Notch to Littleton. The freeway was completed north from New Hampton to Plymouth the following year.
North End – St. Johnsbury, Vermont
South End – Canton, Massachusetts
Two lanes separate from I-93/U.S. 1 south for Interstate 95 south toward Providence, Rhode Island in one half mile. The exchange between the two freeways was originally designed as a full cloverleaf interchange. It was later reconfigured once plans for the alignment taking I-95 northward into Boston were dropped. 10/06/14
Diagrammatic overheads outline the forthcoming trumpet interchange (Exit 12) joining I-95 north with Interstate 93 and U.S. 1 in Canton. 07/29/07
- “$14.6 billion later, Boston’s Big Dig wraps up,” The Christian Science Monitor, December 19, 2003.
- Everett Turnpike (US 3, I-293, and I-93). BostonRoads.com.
- “NH Celebrates 50th Anniversary of Interstate Highway System.” New Hampshire DOT, press release, June 29, 2006.
- “Last stretch of I-93 will open Oct. 29.” The Nashua Telegraph (NH), October 19, 1982.
- Northern Expressway (I-93). BostonRoads.com.
Page updated January 25, 2020.