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CLOSURE: Old Highway 10 will be closed from the Tarkio Fishing Access to the Triple Bridges-Alberton Gorge Recreational Access point. While the Tarkio Fishing Access Road and this section of the Clark Fork River will remain open during the 2026 construction season, access to the east bank of the river will be restricted.

Project Overview

The Montana Department of Transportation (MDT) is developing plans to rehabilitate one bridge and replace two bridges in the westbound lanes of Interstate 90 (I-90) west of Alberton in Mineral County. The bridges carry Interstate 90 over:

  • Old Highway 10 and Elizabeth Lane approximately ten miles west of Alberton
  • Clark Fork River near Alberton Gorge approximately nine miles west of Alberton
  • Clark Fork River near Cyr approximately five miles west of Alberton
Map titled I-90 Bridges West of Alberton. The map shows Interstate 90 (I-90) west of Alberton Montana and east of Superior Montana, between mile markers 65 and 71. Roadways in the image include I-90, Old Highway 10, Fish Creek Road, Elizabeth Lane, Juniper Lane, and Sawmill Gulch Road, with the Clark Fork River depicted running throughout. A compass rose indicates north. The map is not drawn to scale.<br> Bridge repair or replacement locations are marked with dark, orange-colored lines and labeled as follows: On the western end of the project is the I-90 Westbound Old Highway 10/Elizabeth Lane Bridge, noting that work is scheduled to occur in 2026. Heading east on I-90, next is the I-90 Westbound Clark Fork River Bridge over Alberton Gorge that is scheduled for replacement from 2026 to 2028. Continuing east, the last bridge depicted is the I-90 Westbound Cyr Bridge that travels over the Clark Fork River and is tentatively scheduled to be rehabilitated in 2027.<br> A portion of Old Highway 10 from the Tarkio Fishing Access to the Alberton Gorge Recreation Area is closed and marked in yellow.
Map titled I-90 Bridges West of Alberton. The map shows Interstate 90 (I-90) west of Alberton Montana and east of Superior Montana, between mile markers 65 and 71. Roadways in the image include I-90, Old Highway 10, Fish Creek Road, Elizabeth Lane, Juniper Lane, and Sawmill Gulch Road, with the Clark Fork River depicted running throughout. A compass rose indicates north. The map is not drawn to scale.
Bridge repair or replacement locations are marked with dark, orange-colored lines and labeled as follows: On the western end of the project is the I-90 Westbound Old Highway 10/Elizabeth Lane Bridge, noting that work is scheduled to occur in 2026. Heading east on I-90, next is the I-90 Westbound Clark Fork River Bridge over Alberton Gorge that is scheduled for replacement from 2026 to 2028. Continuing east, the last bridge depicted is the I-90 Westbound Cyr Bridge that travels over the Clark Fork River and is tentatively scheduled to be rehabilitated in 2027.
A portion of Old Highway 10 from the Tarkio Fishing Access to the Alberton Gorge Recreation Area is closed and marked in yellow.

These bridge improvements will serve Montana and the traveling public well into the future, providing low-maintenance features, and enhanced safety improvements to meet anticipated transportation needs. Design plans include:

  • Painting portions of the I-90 Elizabeth Lane Bridge below the bridge deck (driving surface) to slow corrosion.
  • Replacing the westbound I-90 Cyr Bridge and upgrading guardrails and drainage.
  • Replacing the westbound I-90 Alberton Gorge Bridge and upgrading guardrails and drainage.

Why

The bridges were originally constructed in 1965 and although they are still safe to travel on, they have aged to the extent that replacing two of the bridges is needed. In certain situations, MDT is able to rehabilitate a structure instead of replacing it. Rehabilitation involves a structure having one or more components which still have a substantial amount of service life remaining. However, the steel beams called girders on the I-90 Cyr Bridge and I-90 Alberton Gorge Bridge have aged to the point that rehabilitation or spot repairs are no longer cost-effective, practical solutions. The improved bridge structures will serve Montana and the traveling public well into the future, providing low-maintenance improvements and enhanced safety features to meet anticipated transportation needs.

I-90 Clark Fork River Bridge/Cyr
I-90 Clark Fork River Bridge/Cyr
I-90 Clark Fork River Bridge/Alberton Gorge
I-90 Clark Fork River Bridge/Alberton Gorge

Anticipated Schedule

MDT is currently in the project design development process and will update the public at key points throughout the design process. The design plans are anticipated to be completed in 2025. Construction is dependent on the availability of funding and will be scheduled once the design plans are finalized.

Stay Involved

The public will be notiļ¬ed about public involvement opportunities through the project website, local media, mailings, social media and other communication channels. Public input will help guide MDT in the design and construction of the bridge improvements. MDT plans to engage key project stakeholders and the public to gain information that will be used in the planning process.

UPN 9786000