On this day in history – March 23, 1977 – the Francis Scott Key Bridge that spans the Patapsco River in Baltimore opened to traffic. Besides the famous name, the bridge was a major milestone in Maryland’s transportation planning and remains the second longest continuous truss bridge in the United States.

[Edited to note that this post originally appeared on our website on March 23, 2017. On March 26, 2024, the Key Bridge was tragically struck by a ship, The “Dali,” and was a total loss. As of the time of this edit, the full story of its destruction is not yet known, but lives are feared lost in this unfolding tragedy.]

While most Marylanders have heard of Francis Scott Key and his poem that inspired the Star Spangled Banner, many may not know the story of the bridge that bears his name.

The Key Bridge was a major milestone for the development of the Maryland highway system as it completed the Interstate 695 circuit around Baltimore. It is also a significant engineering accomplishment – and it is one of the longest continuous truss bridges in the United States.

To address Baltimore’s growing problem with traffic congestion, the State Roads Commission, predecessor of the Maryland Transportation Authority, suggested a second tunnel be constructed to reduce traffic volume through the Baltimore Harbor Tunnel. After project proposals proved too expensive, state officials proposed a four-lane bridge that would carry more traffic, allow for transportation of hazardous materials and have lower operating costs than a tunnel.

Construction began in August 1972 with the Baltimore firm J. E. Greiner Company serving as the primary engineering consultant. Originally expecting to build a two-lane tunnel, contractors built two-lane approaches on both sides of the harbor, which were not widened to four lanes until 1981. The northern approach had an elevated viaduct and bridge over Bear Creek and passed by Bethlehem Steel complex at Sparrow’s Point. This section of the bridge highway was widened and reconnected to other roads in 2000.

The southernmost transportation route across the Patapsco River, the Key Bridge, runs 1.6 miles and connects Sollers Point to Hawkins Point. The continuous steel truss bridge is 185 high and spans a distance of 1,200 feet. Including connecting approaches, the bridge is 10.9 miles long. Funded entirely by Maryland Transportation Authority toll bonds, the bridge cost $60.3 million. These days, the bridge carries an average of 10.4 million vehicles across the Patapsco River each year.


Historians believe the bridge is within 100 yards of where Francis Scott Key was kept aboard the British flagship HMS Tonnant and wrote his famous poem that went on to become the National Anthem of the United States. On the southern side of the bridge is another monument to 19th century Baltimore history – Fort Carroll. Named after Charles Carroll (1737-1832), a Maryland political leader and the last surviving signer of the Declaration of Independence, the fort sits abandoned near the opening to the Chesapeake.

Constructed between 1847 and 1850, the fort was built by the U.S. War Department to suppliment the protections offered by Fort McHenry, but proved ineffective especially due to frequent flooding that spoiled ammunitions and thus, the fort was used minimally between the Civil War and the Spanish-American War. Later, a lighthouse to help ships avoid the fort and demarcate two lanes for marine traffic, yet the Army abandoned the fort in 1921. Ownership of the land and the fort changed hands several times and still remains abandoned and decaying.

This essay was researched and written by Kyle Fisher a former Preservation Maryland’s Waxter Intern. With degrees in history, communications, and teaching, Kyle has contributed greatly to our education and outreach programs. Learn more about Kyle and our intern program here: presmd.org/waxter.

Image via Patorjk, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons