Hosston to Plain Dealing bridge over the Red River in Louisiana.

Iron, wedded with other materials like brick and stone, has been used in bridge construction since the 18th century. The very first all-iron bridge, in an arch design, was built in England. Iron truss bridges, which were based on wooden bridge designs, became popular in America. Forged in foundries in the mid-Atlantic and mid-western states, the bridges could be shipped via rail and then assembled on site. They were painted either red or orange to hide the rust that would inevitably develop. By the mid-20th century, rust-resistant steel replaced iron as the material of choice. The iron works who competed against each other in bridge building offered many different patterns,  so their work can be readily discerned by iron truss bridge aficionados, who can tell just by looking at the lattice and beam work which engineer designed which bridge.

The early bridges were mainly built by private companies who received charters to operate toll bridges across rivers. The Red River Valley had several toll bridges and even more ferry crossings. Railroads, of course, continue to own their bridges, but all bridges across the Red River are now free of charge to cross due to the federalization of highways, an improvement spawned by the Good Roads Movement.

Along the Red River Valley, almost all counties sport at least one old, reliable iron truss. Most people pass by them without nary a glance, but without taking proper care of these bridges, they will become victims to "progress." Farm machinery has become too wide, car traffic too numerous, and rail traffic too little. Sitting on byways in various states of decay, a lot of these bridges are slated for demolition, or at least removal. Civic minded people take it upon themselves to save the trusses - many have found new homes in parks and along walking trails. These old bridges aren't just laying about in silent testimony of our many modes of transportation. By using iron and later, steel, these humble marvels symbolized the America's second Industrial Age.