Mississippi’s Famous Bridges: Record-Breaking Engineering Marvels that United America

It goes by many names. Some are affectionate, like The Ol’ Man Mississippi or The Old Blue Mississippi. Others are reverent, like Father of the Water. And some are less respectful, like The Big Muddy.

And yes, we are talking about the mighty Mississippi River, which flows from Lake Itasca in northern Minnesota all the way to the Gulf of America just past New Orleans, Louisiana, for a total of 3,778 km.

The Mississippi, often seen as the backbone of the continent, is a favorite tourist destination for those who love long riverboat journeys, natural landscapes, and those who want to admire incredible century-old engineering marvels still in use today. The Mississippi is, in fact, a true concentration of historic engineering marvels stretching from source to mouth, in a long journey through ten states.

Some century-old champions are more famous and photographed than others. Here are two steel giants, two great bridges that have towered over America’s most beloved river for decades.

The Eads Bridge in St. Louis, Missouri, is considered the world’s first steel truss bridge and, despite its age, is still an engineering marvel.

It is 1,964 meters long, stands 27 meters above the river, and allows both trains and cars to cross thanks to its two stacked decks.

The bridge was built in 1874, 150 years ago. After the American Civil War and the expansion of the national railway system, the city of St. Louis needed a stable crossing over the Mississippi.

So, in 1867, a group of bankers and businessmen hired James Buchanan Eads (1820–1887), whom city records describe as a self-taught engineer. Mr. Eads had never built a bridge before. But during the Civil War, he had distinguished himself in the construction of military ships.

Time would prove his great engineering talent, and that bridge is still standing today, with enormous granite-clad piers supporting three elegant arches and two decks.

The Eads Bridge was also the first to support railway tracks, the first to use tubular elements, and the first to rely entirely on cantilever construction for its superstructure. For the first time in the United States, pneumatic caissons were used in the construction of the piers, excavated to an unprecedented depth of 38 meters.

Inaugurated on July 4, 1874, the Eads Bridge was declared a National Historic Landmark in 1964.

The Huey P. Long Bridge in New Orleans is one of the tallest and longest steel bridges in America and one of the most fascinating and famous architectural structures, whether crossing it or admiring it from below along the riverbanks. It has six highway lanes and two railway tracks.

Before it was built, railroad cars were ferried across the river on barges, which was both time-consuming and costly.

To put an end to this practice, in 1916 the state of Louisiana decided to build a permanent crossing over the Mississippi, considering three options: a tunnel, a low-level drawbridge, or a high-level bridge. Construction of the third option began in 1925, although financial difficulties slowed progress, delaying completion until 1935.

The bridge, made of steel trusses, required a very high level of maintenance from the start—especially along the tracks—with work crews constantly repainting the structure and replacing the ties (there are 34,704 ties in total, each between 3 and 4.2 meters long and made of southern yellow pine).

The New Orleans bridge spans 7.1 km from end to end, with a main span of 244 meters and a height of 47 meters above the Mississippi. It underwent its most extensive renovation and expansion between 2006 and 2013, though its original structure remained unchanged.

In the wide variety of Mississippi crossings, there are bridges with styles and models no longer in use, because engineering has evolved over time and now enables the creation of safer, more functional structures built with innovative techniques and materials.

It’s no coincidence, in fact, that today both in the U.S. and worldwide, suspension bridges or cable-stayed bridges, as well as arch and truss bridges, are preferred. These styles are still widely represented among the more than 140 bridges currently spanning the Mississippi.

New solutions also allow for what’s called a “change-on-the-go”—the construction of a new structure while the existing one is still in use, which is then dismantled once the new bridge is inaugurated.

Such a project was carried out for the replacement of the Gerald Desmond arch bridge with the brand-new, award-winning Long Beach International Gateway cable-stayed bridge, built in 2020 by Webuild at the Port of Long Beach in California.

The new bridge, built to seismic standards, is a strategic infrastructure not only for California but for the entire U.S. In fact, 15% of goods imported into the U.S. by sea pass through the Port of Long Beach.

The new structure stands out for its 2,700-meter length, a central span of approximately 330 meters, and two side spans each about 150 meters long.