Bitterroot River Bridge

Project Overview

The Montana Department of Transportation (MDT), in cooperation with Missoula County, is proposing to construct a new crossing over the Bitterroot River west of Missoula. The project would enhance safety for the traveling public by constructing a new bridge structure and associated roadway approaches that meet current design standards and future traffic demands. The Bitterroot River Bridge, Missoula, project would construct a new two-lane bridge (one travel lane in each direction) over the Bitterroot River on an extension of South Avenue and remove the Maclay Bridge on North Avenue.

Missoula County, in collaboration with MDT and the Federal Highway Administration (FHWA), is in the process of completing an environmental document (a categorical exclusion CE), required for construction of the proposed bridge. Missoula County submitted the draft CE to MDT and FHWA in November 2022. Section 106 of the National Historic Preservation Act (NHPA) guides federal agencies who propose or permit projects that may affect historic properties. The County is waiting to receive information about the effort required to receive Section 106 approval for adopting and keeping the Maclay Bridge in place as an historic structure.

The County expects FHWA to sign the CE for the new bridge in the summer of 2024. Once the scope of work is finalized, MDT will manage the bridge’s final design and construction with input from Missoula County. Construction is tentatively planned for 2026, depending on completion of design and availability of funding.


The project is in the design phase. Construction is tentatively planned for 2026 and is subject to change dependent on available funding and completion of all project development activities.

Project Partners

HDR is the local engineering firm originally hired by Missoula County and retained by MDT to provide the project design, environmental documentation, and public outreach. HDR has included Tetra Tech and DJ&A on the design team to provide geotechnical design and surveying, respectively.

UPN 6296000