Rainbow Bridge, Valley County

why we care?

Designed by Charles A. Kyle in 1933, the Rainbow Bridge is an open-spandrel arch bridge constructed with reinforced concrete. It is the largest of its type in the state of Idaho and was listed in the National Register of Historic Places in 1999. This bridge is both an integral part of the Payette River Scenic Byway and iconic symbol of southwestern Idaho. The bridge is currently at risk, as the Idaho Transportation Department (ITD) plans to redesign the crossing and construct a replacement bridge.

the threat

In recent meetings with stakeholders, ITD has made public its decision to demolish the Rainbow Bridge as part of their plan to construct a new SH-55 crossing over the North Fork of the Payette River. ITD will construct a new bridge on a straightened alignment to the north (upstream) of the current bridge. The current bridge does not impede the proposed alignment of the new bridge. However, traffic will be discontinued on the existing bridge. ITD has stated that it would be too costly to maintain an abandoned structure in perpetuity, and argues that the bridge must be demolished.

what we want

We believe that in order to ensure fair deliberations regarding the agency’s decision to demolish a cultural resource of such significance, additional information is required. Our organizations request the following information and actions from ITD:

• Documentation, including detailed structural analysis by engineers experienced in the rehabilitation of historic bridges, verifying ITD’s assertion that the preservation of the Rainbow Bridge is not feasible.

• Additional research and consideration of preservation alternatives for the historic bridge including the option for long-term retention in place as a tourist attraction and point of interest. ITD has employed this preservation solution to retain significant historic bridges elsewhere including the US-95 bridge over John Day Creek north of Lucile and the monumental steel and concrete crossing of the active BNSF Railway on US-95 south of Sagle.

• The stakeholder meeting organized by ITD on September 22nd to share their conclusion favoring demolition of the bridge failed to engage all state and local interested parties. Accordingly, we request that ITD hold an open public meeting in Valley County in 2026.

• Clarification, as stated above, regarding the prospect and scheduling of federal environmental and consultation processes.

• An additional meeting with ITD leadership and project planners to discuss the above noted concerns.

what we’re doing

Preservation Idaho has partnered with the Historic Bridge Foundation (a national non-profit), the Idaho Conservation League, Idaho Rivers United, the Ada County and Twin Falls County historic preservation commissions, and the Council Valley Museum.

Together, we have jointly sent a letter to ITD requesting that they reconsider this decision and undertake additional conversations with stakeholders to find a solution that retains the original bridge, rather than demolishing the structure. We are willing to assist ITD in whatever way we can to identify a path forward to preserving this iconic structure. Our organizations stand ready to offer advice, expertise, and contacts in the architectural, engineering, and historic preservation communities to facilitate the retention of this statewide landmark.

Additional Information

Article Links:

“ITD Quietly Proposes Tearing Down Rainbow Bridge”, Local Yocal Idaho. August, 2025. https://localyocalidaho.substack.com/p/itd-quietly-proposes-tearing-down

“Is it too late to save Idaho’s iconic Rainbow Bridge?”, Idaho Statesman. August, 2025. https://www.idahostatesman.com/opinion/from-the-opinion-editor/article311583640.html

“Historic Rainbow Bridge on Highway 55 may be dismantled due to safety concerns and high costs”, Idaho 6 News. July, 2025. https://www.kivitv.com/valley-county/historic-rainbow-bridge-on-highway-55-may-be-dismantl ed-due-to-safety-concerns-and-high-costs

“ITD plans to tear down historic Rainbow bridge”, Valley Lookout. July, 2025. https://valleylookout.com/2025/07/28/itd-rainbow-removal/

Material Links:

National Register of Historic Places Registration Form. NORTH FORK PAYETTE RIVER BRIDGE, NPS. 1999. https://history.idaho.gov/wpcontent/uploads/2018/09/North_Fork_Payette_River_Bridge_99000416.pdf

Historic Photographs of the Rainbow Bridge Blog Article. Yellow Pine Times. January, 2017. https://yellowpinetimes.wordpress.com/2017/01/01/idaho-history-jan-1-2017/

Payette River National Scenic Byway: History. https://payetteriverscenicbyway.org/history/

ITD Charles A Kyle Poster. https://apps.itd.idaho.gov/apps/env/cultural/ENV_CharlesKyle.pdf

ITD: Cultural Resources. https://itd.idaho.gov/environmental/cultural-resources/