Maryland's geography, dominated by the Chesapeake Bay and its many tidal rivers, has necessitated some impressive feats of engineering to connect its communities. While the state is famous for its massive bridges, it is also home to several major underwater tunnels. Among these, one stands out for its incredible length and vital role in the East Coast's most important highway: the Fort McHenry Tunnel in Baltimore, the longest tunnel in the state of Maryland.
The Champion of Length: The Fort McHenry Tunnel
The Fort McHenry Tunnel is a critical piece of infrastructure for both Baltimore and the entire I-95 corridor.
- Length: The tunnel stretches for approximately 1.5 miles (or about 7,920 feet) under the Patapsco River, just south of the historic Fort McHenry.
- Route: It carries Interstate 95 through the city, providing a crucial link for traffic traveling between Washington, D.C., Baltimore, Philadelphia, and New York. It is the preferred route for most hazardous materials that are prohibited from using the nearby Francis Scott Key Bridge (before its collapse) and the Baltimore Harbor Tunnel.
- Design: It is a twin-tube tunnel, with two separate bores each carrying two lanes of traffic, for a total of four lanes in each direction (eight lanes total).
A Landmark Engineering Achievement:
Opened to traffic in November 1985, the construction of the Fort McHenry Tunnel was a monumental undertaking.
- Construction Method: It was built using the immersed tube method, where massive pre-fabricated concrete and steel tunnel sections were constructed off-site, floated into place, sunk into a trench dredged in the river bottom, and then connected together underwater.
- Significance: At the time of its opening, it was the widest and largest underwater highway tunnel in the world. It was designed to alleviate traffic congestion from the older Baltimore Harbor Tunnel and to complete a key section of I-95 through the city. The project's design also carefully considered the historical importance of nearby Fort McHenry, ensuring the tunnel would not detract from the landmark.
Other Notable Tunnels in Maryland:
- Baltimore Harbor Tunnel: Opened in 1957, this 1.4-mile-long tunnel carries Interstate 895 under the Patapsco River. It was the primary harbor crossing before the Fort McHenry Tunnel was built.
- Howard Street Tunnel: A historic railroad tunnel running under downtown Baltimore, it is approximately 1.7 miles long. While longer than the Fort McHenry Tunnel, it is a single-track rail tunnel and not a highway, making the Fort McHenry Tunnel the longest vehicular tunnel in the state.
The Fort McHenry Tunnel is unequivocally the longest highway tunnel in Maryland, serving as a vital artery for the millions of travelers and commercial vehicles that use the I-95 corridor each year. This impressive engineering marvel not only facilitates transportation but also stands as a testament to the innovative solutions required to navigate the unique geography of the Old Line State.
Sources:
- Maryland Transportation Authority (MDTA)
- Maryland Department of Transportation (MDOT)
- U.S. Department of Transportation - Federal Highway Administration (FHWA)
- Historical engineering and construction records for the I-95 corridor
- Local news archives from The Baltimore Sun covering the tunnel's construction and opening
