What type of bridge is the Rainbow Bridge on former U.S. Route 66 near Riverton, Kansas?

The Rainbow Bridge near Riverton, Kansas, is a single-span concrete Marsh arch bridge.

Built in 1923 over Brush Creek, the bridge later became part of the Route 66 corridor. It was designed using the Marsh arch system, a distinctive reinforced-concrete form developed by engineer James Barney Marsh.

The Rainbow Bridge is especially notable because it is the sole surviving bridge of this type along the entire former Route 66 alignment. Two other Marsh arch bridges once stood on Route 66 in Kansas, but they crossed the Spring River and no longer survive in the same form.

The bridge was added to the National Register of Historic Places in 1983 under the name Brush Creek Bridge. It remains associated with a drivable county road and is an important preservation landmark in Kansas’s short Route 66 segment.