5/14/2026
Jill Youmans
ITD Communication
208.334.8303
jill.youmans@itd.idaho.gov
ITD will present new Rainbow Bridge design at open house on May 21
VALLEY COUNTY – The Idaho Transportation Department will host a community open house Thursday to present the new design to replace the Rainbow Bridge on State Highway 55.
Community members may attend in person at the American Legion Post 60 in Cascade (105 E. Mill St, Cascade, ID 83611) on Thursday, May 21, anytime between 4 p.m. and 7 p.m. Those unable to attend the open house can view materials and provide feedback online at the project website until June 4.
The open house will include:
- A project update.
- The new bridge design.
- An opportunity to give feedback about aesthetic features including possible artwork to honor the historic bridge.
Nearly a century after its construction, the current Rainbow Bridge no longer meets ITD standards for state highway bridges. The new bridge design will improve safety by eliminating tight curves on both sides of the bridge, increasing sight distance for motorists, and accommodating wider and longer vehicles.
ITD has gathered public input throughout the design process through community open houses, online feedback opportunities, outreach at the Valley County Fair and a dedicated Bridge Involvement Group that meets before each public meeting. The first round of open houses was held in July 2024 followed by a second round in July and August 2025. Comments from community members and stakeholders helped narrow nine original bridge concepts to four options for further evaluation, with feedback priorities focused on maintaining an iconic design, avoiding a “false historic” appearance and reducing long-term maintenance concerns.
Information from past public meetings and Bridge Involvement Group meetings is available at the project website.
