“A massive interchange” is quite the understatement when describing the South Bay Interchange. This colossal network of roads dominates downtown Boston. It is a vital, yet often overlooked, piece of the city’s infrastructure.
The South Bay Interchange is where Interstate 90, the Mass Pike Extension, and Interstate 93 converge. US 1 and MA 3 also join this concrete dance south of the Thomas P. O’Neill Jr. Tunnel.
This interchange sprawls across the South Bay parcel. This parcel is a 10-acre site wedged between Chinatown and the Leather District. Kneeland Street, Hudson Street, the Massachusetts Turnpike mainline, and the Interstate 93 mainline roughly define its borders.
Currently, the Massachusetts Department of Transportation owns and maintains this crucial area. It is a major highway interchange connecting 90, 93, and local streets. Imagine the sheer volume of traffic flowing through here daily.
Interestingly, there were once ambitious plans for this space. The vision included a 600-foot tall office tower. But, alas, that project never materialized. The South Bay Interchange remains solely a transportation hub.
The land beneath the South Bay Interchange has its own story. This area, along with Chinatown and the Leather District, sits on filled land. It was once part of South Cove, an extension of Boston’s South Bay.
In 1833, the South Cove Corporation filled in the area. They built an intermodal train and sea station for the Boston and Worcester Railroad. This development included residential and commercial spaces, and what was then the largest hotel in the United States.
Throughout much of the 19th and early 20th centuries, the district served as rail yards. These yards were crucial for railroads entering Boston from the south and west.
The railroads attracted leather and garment businesses. They constructed commercial buildings in the adjacent Leather District. The railroad also became an immigrant gateway. Many Asian newcomers, particularly Chinese, arrived this way in the late 19th century.
In the 1950s, the Massachusetts Highway Department displaced many rail yards. They needed space to build the John F. Fitzgerald Expressway, also known as the Central Artery. Later, the South Bay Interchange connected the Central Artery to the Massachusetts Turnpike.
The Big Dig project reconstructed this intersection. Tunnels were added leading to South Boston and Logan Airport. It was an immense undertaking.
Construction on the South Bay Interchange began in the late 1990s. It was a major part of the Big Dig project. Engineers used innovative methods to minimize disruptions. Soil freezing and tunnel jacking were among them. These techniques allowed them to maintain subway, freight, and commuter rail operations.
The name “South Bay” comes from the area’s original state. Before 19th-century land reclamation, it was a marshy, brackish estuary of Boston Harbor. Dirt from nearby high ground filled this area.
The South Bay Interchange stands as a testament to Boston’s ever-evolving landscape. It connects the city and its people. While it may not be the most glamorous landmark, its function is undeniably vital. It keeps Boston moving.