Marsh Rainbow Arch Bridge

Marsh Rainbow Arch Bridge is a concrete road bridge featuring two curved ribs on each side of the roadway, with the deck suspended by vertical supports above. The structure spans roughly 46 feet (14 meters) and displays the distinctive curved form that gives the design its name.

James Barney Marsh designed and built this concrete bridge in 1911, the same year he patented his rainbow arch design. The structure was a pioneering construction that demonstrated new possibilities for bridge engineering and was later copied in many projects.

The bridge shows how Iowa engineering evolved in the early 1900s, marking the shift from wooden structures to reinforced concrete construction. You can see how this design represented a major advancement that influenced later bridge building across the region.

The bridge no longer carries vehicle traffic and is preserved as a historical site, so visitors can view it from ground level or nearby. The best perspective is from the side, where you can see the distinctive arch form and the structural details.

This ranks among the earliest documented rainbow arch bridge designs in the entire United States, which intensifies its value as an engineering landmark. The structure shows how local engineers stood at the forefront of concrete construction innovations.