Interstate 93 (I‑93) is a north–south Interstate Highway in the United States that runs through the New England region, connecting the states of Massachusetts, New Hampshire, and Maine. The highway is part of the Dwight D. Eisenhower National System of Interstate and Defense Highways.
Route description
- Length: Approximately 197 mi (317 km).
- Southern terminus: Boston, Massachusetts, at the junction with Interstate 95 (Route 1A) near the South Bay interchange.
- Northern terminus: Near Houlton, Maine, at the Canada–United States border where it becomes New Brunswick Route 95.
- States traversed: Massachusetts, New Hampshire, Maine.
- Major cities and towns served: Boston (MA), Concord (NH), Manchester (NH), Nashua (NH), Portland (ME), Augusta (ME), and Houlton (ME).
The highway follows a generally northeastward alignment from Boston, crossing the Charles River via the Leverett Street Bridge, and proceeds through the densely populated Boston metropolitan area. It then continues through the Merrimack River valley, passing through the capital cities of Concord and Manchester before entering the White Mountains region of New Hampshire. In Maine, I‑93 runs parallel to the Kennebec River and later the Androscoggin River, providing primary access to central and northern parts of the state.
Historical development
- Planning and designation: I‑93 was designated as part of the original Interstate Highway System in the 1950s. The route was selected to provide a high‑capacity corridor linking Boston with the Canadian border, facilitating both commercial traffic and regional mobility.
- Construction milestones: The first segments in Massachusetts were completed in the early 1960s, including the Central Artery (now part of the "Big Dig" project). The New Hampshire portion, notably the segment through the White Mountains, was finished in the late 1960s and early 1970s. The final extension to the Houlton border in Maine was opened in 1973.
- Major upgrades: Significant improvements have included the replacement of the original viaducts in Boston with the tunnel system completed in 2005, the widening of sections in New Hampshire to six lanes near Manchester, and ongoing safety upgrades in mountainous terrain.
Major interchanges and auxiliary routes
- Interstate 95 (I‑95): Interchange in Boston, providing connections to the New England coastal corridor.
- Interstate 495 (I‑495): Interchange near Andover, Massachusetts, serving the outer Boston beltway.
- Interstate 293 (I‑293): A short auxiliary route in Manchester, New Hampshire, connecting I‑93 with I‑93’s western bypass.
- U.S. Route 1 (US 1) and U.S. Route 2 (US 2): Various junctions in Maine provide access to coastal and inland destinations.
Traffic and usage
I‑93 carries a mixture of commuter, commercial, and tourist traffic. The Boston–Manchester segment experiences high daily vehicle volumes, particularly during peak commuting periods, while the more rural sections in New Hampshire and Maine have lower traffic densities but are critical for regional freight movement and access to recreational areas such as the White Mountains and the Appalachian Trail.
Future plans
State transportation agencies have outlined projects to improve safety and capacity, including additional lane expansions near urban interchanges, implementation of intelligent transportation systems for real‑time traffic management, and reconstruction of aging bridge structures in Maine. Funding and timelines are subject to state and federal budget allocations.
References
- Federal Highway Administration, “Interstate System Route Log and Finder List,” 2022.
- Massachusetts Department of Transportation, “Interstate 93 Project Documentation,” 2021.
- New Hampshire Department of Transportation, “I‑93 Corridor Improvement Program,” 2020.
- Maine Department of Transportation, “Interstate 93: History and Planning,” 2019.
