Sixmile Creek Wildlife Crossing Study project logo

Study Focus

The Montana Department of Transportation (MDT) is conducting an engineering feasibility study to replace the 60-year-old, hydraulically undersized Sixmile Creek culvert with two large open-span bridges: one for westbound traffic and one for eastbound traffic. These open-span bridges will provide a wildlife underpass that, when combined with fencing to funnel animals to the crossing, is a proven tool to reduce animal-vehicle collisions while offering suitable and safe crossing opportunities for a host of terrestrial and aquatic species, including grizzly bears, black bears, elk, deer, and native fish. An improved underpass at Sixmile Creek would be paired with wildlife exclusion fencing at the bridges over the Clark Fork River in the Ninemile area to encourage wildlife to use those existing underpass structures.

The study will also evaluate the feasibility of additional wildlife features associated with the project including "jump outs," or earthen mounds built up against the fence to allow animals to jump down quickly out of the interstate right-of-way to the safe side of the fence, double cattle guards, and electric mats at the Huson and Ninemile Exit Interstate 90 (I-90) Interchanges. The study will also include conceptual stream restoration design through the study area.

The project was proposed by the Missoula Regional Connectivity Group (MRCG) through the Montana Wildlife and Transportation Partnership Program.

Sixmile Creek culvert (photo by HDR)

Project Location Map

Sixmile Creek Wildlife Crossing Study project map

The Sixmile Creek Wildlife Crossing Study is located in Missoula County on I-90 from mile marker 79.3 to 86.6.

Stay Informed, Stay Involved

In addition to stakeholder meetings, the project team will communicate with you using this project website. The project will include an in-person and virtual public meeting to be held tentatively in Fall 2025.

New project information will be posted on this website as it becomes available, but you can request to be added to our mailing list or submit your comment electronically. To send us your U.S. mail or email address, or to submit a comment, visit MDT’s Online Comment Form.

Please note that your comments are for the Sixmile Creek Wildlife Crossing Study, UPN 10566000. Thank you!